BIO EXAM Practice Questions

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Which is not a monophyletic clade in this tree.

(A, C, B, D, F)

In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of the allele a is 0.3. What is the frequency of individuals that are homozygous for this allele? A) 0.09 B) 0.49 C) 0.9 D) 9.0

0.09

0.50

In peas, a gene controls flower color such that R = purple and r = white. In an isolated pea patch, there are 36 purple-flowering plants and 64 white-flowering plants. Assuming Hardy-Weinberg equilibrium, what is the value of q for this population? A) 0.36 B) 0.64 C) 0.75 D) 0.80

0.80

In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.1. What is the frequency of individuals with AA genotype? A) 0.20 B) 0.32 C) 0.42 D) 0.81

0.81

Which of the characters in the matrix below are synapomorphies that are useful in determining the evolutionary relationships betweenthe 5 species listed?

2, 4, 5

In Kerr and Wright's experiment with 96 fruit-fly populations, only 4 males and 4 females bred in each generation. After 16 generations, 73% of their populations had only one allele present for the bristle morphology gene. Which of the following would you expect to occur if they allowed 10 males and 10 females to breed each in generation?

2. Less than 73% with a larger population sample, the outcome will be closer to the predicted outcome

In a population of toads, allele A is present at a frequency of 0.2, and allele a is present at a frequency of 0.8. Based on Hardy-Weinberg expectations, what is the expected frequency of the genotype Aa in the population?

2pq = 2(0.2)(0.8) = 0.32

According to the Hardy-Weinberg Equilibrium, there will not be evolution if five conditions are met. Which of the following is not one of these conditions? A. The population must be small. B. There can be no mutations. C. All offspring must have an equal chance of survival (no natural selection). D. There can be no gene flow due to migration. E. Reproduction must be random.

Among allopatric species of Anopheles mosquito, some live in brackish water, some in running fresh water, and others in stagnant water. What type of reproductive barrier is most obviously separating these different species? A. pre-zygotic barriers B. post-zygotic barriers C. all of the above

Cystic fibrosis is a genetic disorder in homozygous recessive (ff) that typically causes death in the early 30s. Over time, we would expect the f allele frequency to ___ for this trait. A. decrease B. increase C. remain the same D. fluctuate

In a hypothetical environment, fishes called pike-cichlids are visual predators of algae-eating fish (i.e., they locate their prey by sight). If a population of algae-eaters experiences predation pressure from pike-cichlids, which of the following should least likely be observed in the algae-eater population over the course of many generations? A. Selection for larger female algae-eaters, bearing broods composed of more, and larger young B. Selection for algae-eaters that become sexually mature at smaller overall body sizes C. Seclection for nocturnal algae-eaters (active only at night) D. Selection for algae-eaters that are faster swimmers E. Selection for drab coloration of the algae-eaters

The introduction of antibiotics such as penicillin during World War II was immediately effective in combating infections caused by Staphylococcus sp. In 1958, however, there were several outbreaks of staphylococcal infections. People with the infections did not respond to treatment with any of the conventional antibiotics and there were a large number of deaths. The best explanation for this situation is that A. antibiotic-resistant bacteria, resulting from random mutations, survived and multiplied, and these were the forms causing the infections. B. the bacteria from other hosts such as birds, cats, and dogs migrated into human hosts. C. each generation of bacteria acquired the ability to use antibiotics as nutrients. D. the bacteria reproduced in hosts that were not contaminated with antibiotics. E. the bacteria exposed to non-lethal doses of antibiotics quickly leaned to avoid them.

Which of the following is not an observation or inference on which natural selection is based? A. Poorly adapted individuals never leave offspring. B. Individuals whose inherited characteristics best fit them to the environment will generally leave more offspring. C. There is heritable variation among individuals. D. There is a struggle for limited resources, and only a fraction of offspring survive.

Which of the following is the best modern definition of evolution? A. change in allele frequencies in a population over time B. descent without modification C. inheritance of acquired characters D. survival of the fittest

Why did Darwin argue that evidence of extinction supports the theory of evolution? A. It shows that the number and types of species have changed over time. B. It shows that nothing lasts forever. C. It shows that reproduction is more important than survival of the fittest. D. It shows that lower organisms have died to make way for humans.

Which of the following is the best description of the epiglottis?

A flap of cartilage that flips down to cover the entry to the trachea during swallowing

Which situation would most likely lead to allopatric speciation? A. flood causes the formation of a new lake. B. A storm causes several large trees to fall down. C. A mutation causes a new trait to develop. D. An injury causes an organism to seek out a new food source.

A flood causes the formation of a new lake

allopatric speciation

A large population of animals is split in two by a physical barrier. The gene pools of the two resulting populations then diverge until each population becomes a separate species.

Assume that the reproductive isolation seen in Phlox strains results from lethal combinations of incompatible alleles at several loci among the various strains. Given this assumption, why might the reproductive isolation seen among these strains be partial rather than complete?

A likely possibility is that the incompatible alleles have not yet become fixed in the various strains, so only some combinations of crosses result in genetic incompatibility.

Which of the following men has higher evolutionary fitness?

A man that dies at 30, after fathering 5 healthy children

Why do adaptive radiations often occur when a founder species invades an isolated geographic area?

A new immigrant to an isolated area may encounter no competition for a particular feeding strategy or life style. Under these conditions, there are many "open niches" that can be co-opted by the invading species, leading to a rapid increase in speciation.

Can you think of reasons why gene flow might slow the evolution of a population?

A small population might be under strong selection for a particular trait that is favored locally. However, if there is extensive gene flow from neighboring populations where the particular trait is not favored, then selection for the trait in question will be overwhelmed by the gene flow from the surrounding populations.

You are the lucky student of a wacky professor who develops a time machine. He asks if you will test it with him. You get in and there is an immediate glitch-the date readout fails so that when you land you are not sure what era you are in. As your time machine lands, you see an unusual landscape before you. As you open the door you realize you cannot breathe. You quickly shut the door, realizing you are in the _____. A) Archaean eon B) Cambrian period C) Cenozoic era D) Mesozoic era a

A) Archaean eon

How do stabilizing and disruptive selection differ? A) Stabilizing selection reduces the amount of variation in a trait. Disruptive selection increases the amount of variation in a trait. B) With stabilizing selection, extreme individuals have high biological fitness. With disruptive selection, extreme individuals have low biological fitness. C) With stabilizing selection, the phenotype for a trait does not influence survival. With disruptive selection, the phenotype for a trait affects survival. D) Stabilizing selection produces adaptation. Disruptive selection is nonadaptive.

A) Stabilizing selection reduces the amount of variation in a trait. Disruptive selection increases the amount of variation in a trait.

Which of Darwin's postulates about evolution by natural selection is most directly related to heritable variation? A) The individual organisms that make up a population vary in the traits they possess. B) Individuals that survive are not a random sample of the population. C) In each generation, many more offspring are produced than can possibly survive. D) An individual's phenotype can change in response to a challenge from the environment.

A) The individual organisms that make up a population vary in the traits they possess.

How might paleontologists be misled by their observations of fossils? A) They typically only find species that were widespread and/or present on the Earth for long periods of time. B) Fossil finds are typically limited to species within the past 100,000 years. C) Paleontologists lack the biological training to make proper conclusions. D) They typically find odd and rare species that might not represent the Earth at that time.

A) They typically only find species that were widespread and/or present on the Earth for long periods of time.

Whatever its ultimate cause(s), the Cambrian explosion is a prime example of _____. A) adaptive radiation B) evolutionary stasis C) a large meteor impact D) mass extinction

A) adaptive radiation

Which variable is likely to undergo the largest change in value resulting from a mutation that introduces a new allele into a population at a locus for which all individuals formerly had been fully homozygous? A) average heterozygosity B) nucleotide variability C) geographic variability D) average number of loci

A) average heterozygosity

You are maintaining a small population of fruit flies in the laboratory by transferring the flies to a new culture bottle after each generation. After several generations, you notice that the viability of the flies has decreased greatly. Recognizing that small population size is likely to be linked to decreased viability, the best way to reverse this trend is to _____. A) cross your flies with flies from another lab B) reduce the number of flies that you transfer at each generation C) transfer only the largest flies D) change the temperature at which you rear the flies

A) cross your flies with flies from another lab

Which of the following is the most predictable outcome of increased gene flow between two populations? A) decreased genetic difference between the two populations B) higher average fitness in both populations C) lower average fitness in both populations D) increased genetic drift E) increased genetic difference between the two populations

A) decreased genetic difference between the two populations

Mutation is the only evolutionary mechanism that _____. A) does little to change allele frequencies B) is more important in eukaryotes than in prokaryotes C) happens in all populations D) has no effect on genetic variation

A) does little to change allele frequencies

Cystic fibrosis is a genetic disorder in homozygous recessives that causes death during the teenage years. If 9 in 10,000 newborn babies have the disease, what are the expected frequencies of the dominant (A1) and recessive (A2) alleles according to the Hardy-Weinberg model? A) f(A1) = 0.9700, f(A2) = 0.0300 B) f(A1) = 0.9604, f(A2) = 0.0392 C) f(A1) = 0.9800, f(A2) = 0.0200 D) f(A1) = 0.9997, f(A2) = 0.0003 E) f(A1) = 0.9600, f(A2) = 0.0400

A) f(A1) = 0.9700, f(A2) = 0.0300

The restriction enzymes of bacteria protect the bacteria from successful attack by bacteriophages, whose genomes can be degraded by the restriction enzymes. The bacterial genomes are not vulnerable to these restriction enzymes because bacterial DNA is methylated. This situation selects for bacteriophages whose genomes are also methylated. As new strains of resistant bacteriophages become more prevalent, this in turn selects for bacteria whose genomes are not methylated and whose restriction enzymes instead degrade methylated DNA. The outcome of the conflict between bacteria and bacteriophage at any point in time results from _____. A) frequency-dependent selection B) evolutionary imbalance C) heterozygote advantage D) neutral variation

A) frequency-dependent selection

Refer to the paragraph on dark-eyed junco birds. The UCSD campus male junco population tails are about 36% white, whereas the tails of males from nearby mountain populations are about 40-45% white. The founding stock of UCSD birds was likely from the nearby mountain populations because some of those birds overwinter on the UCSD campus each year. Population sizes on the UCSD campus have been reasonably large, and there are significant habitat differences between the UCSD campus and the mountain coniferous forests; UCSD campus has a more open environment (making birds more visible) and a lower junco density (decreasing intraspecific competition) than that in the mountain forests. Given this information, which of the following evolutionary mechanisms do you think is most likely responsible for the difference between the UCSD and mountain populations? A) natural selection B) genetic drift C) gene flow D) mutation

A) natural selection

The best classification system is that which most closely _____. A) reflects evolutionary history B) reflects the basic separation of prokaryotes from eukaryotes C) conforms to traditional, Linnaean taxonomic practices D) unites organisms that possess similar morphologies

A) reflects evolutionary history

Adult male humans generally have deeper voices than do adult female humans, which is the direct result of higher levels of testosterone causing growth of the larynx. If the fossil records of apes and humans alike show a trend toward decreasing larynx size in adult females and increasing larynx size in adult males, then _____. A) sexual dimorphism was evolving over time in these species B) intrasexual selection seems to have occurred in both species C) stabilizing selection was occurring in these species concerning larynx size D) selection was acting more directly upon genotype than upon phenotype

A) sexual dimorphism was evolving over time in these species

The inability of organisms to evolve anything that could be an advantage reflects _____. A) the limits of historical constraints B) the inability to compromise C) the consequences of random mutations D) the consequences of inbreeding

A) the limits of historical constraints

The following sample lists the genotype at locus A for 10 individuals in a diploid population: AA, AA, Aa, Aa, Aa, Aa, aa, aa, aa, aa. A. Based on this sample, what is the observed frequency of allele a? The observed frequency of allele A? B. What are the observed frequencies of genotypes aa, Aa, and AA? C. After one generation of random mating, what would be the Hardy-Weinberg expectations for the frequencies of genotypes aa, Aa, and AA?

A. Frequency of allele a: 0.60; of allele A: 0.40; B. Frequency of genotype aa: 0.40; of genotype Aa: 0.40; of genotype AA: 0.20; C. Expected frequency of genotype aa: 0.36; of genotype Aa: 0.48; of genotype AA: 0.16

Why is speciation by polyploidy more likely in plants than in animals? A. Plant gametes can be produced from somatic cells that have undergone many rounds of mitosis. B. Plant gametes lack postzygotic isolating mechanisms. C. Plants are sessile and, therefore, are never prezygotically isolated to ensure reproduction. D. Plants are sessile and cannot speciate via dispersal. E. Plants lack the DNA repair enzymes that animals have.

A. Plant gametes can be produced from somatic cells that have undergone many rounds of mitosis.

Fitness is evaluated on the basis of which of the following? A. The number of offspring produced B. The general health and strength of an individual C. The age of an individual D. The phenotypic characteristics of an individual E. The amount of weight an individual can bench press

A. The number of offspring produced

What is the evidence for toe-pad evolution in the populations of A. carolinensis on the invaded islands? Why have toe pads in these populations of A. carolinensis changed so rapidly?

A. carolinensis from islands with introduced A. sagrei have significantly larger toepads with more lamellae compared to lizards from islands without A. sagrei. As the A. sagrei were only introduced to the islands in 1995, these differences in foot structure appear to have arisen since that time. The fact that the toepads have evolved so quickly indicates that there is strong selection for larger toepads with more lamellae in lizard populations on the invaded islands.

Population genetics is the study of: A. how selective forces change the allele frequencies in a population over time B. the genetic basis of population-wide traits C. whether traits have a genetic basis D. the degree of inbreeding in a population

A. how selective forces change the allele frequencies in a population over time

When males and females of a population look or act differently, it is referred to as ________. A. sexual dimorphism B. sexual selection C. diversifying selection D. a cline

A. sexual dimorphism

Homologous traits are A. traits that are similar in form due to shared common ancestry B. traits derived from different ancestors and thus are unrelated. C. traits that are the result of convergent evolution D. traits that result from genetic and developmental similarities

A. traits that are similar in form due to shared common ancestry

What is assortative mating? A. when individuals mate with those who are similar to themselves B. when individuals mate with those who are dissimilar to themselves C. when individuals mate with those who are the most fit in the population D. when individuals mate with those who are least fit in the population

A. when individuals mate with those who are similar to themselves

Of the following scenarios, which would provide the best analogy for describing the process of constructing a phylogenetic tree using genetic information?

A.Assembling a jigsaw puzzle

In the tutorial, you observed the results of laboratory experiments with flowering plants that were engineered to have resistance to an herbicide. The experiments demonstrated that maintaining this resistance came at the cost of reducing the number of seeds produced by the plants. Why might it never be possible for both herbicide resistance and high level seed production to exist simultaneously in the same plant?

A.The plant may reduce seed production as a first line of action whenever any new adaptation requires energy expenditure.

In the following figure, the isthmus separates the Pacific Ocean on the left (side A) from the Atlantic Ocean on the right (side B). The seawater on either side of the isthmus is separated into five depth habitats (1—5), with 1 being the shallowest. The Panama Canal was completed in 1914, and its depth is about 50 feet. After 1914, snapping shrimp species from which habitats should be most likely to form hybrids as the result of the canal?

A1 and B1

When an organism dies, its muscles remain in a contracted state termed "rigor mortis" for a brief period of time. Which of the following most directly contributes to the phenomenon? There is no

ATP to break bonds between the thick and thin filaments

Which of the following describes the stage of the cardiac cycle shown in the figure of the heart to the right?

AV valves closed, SL valves open...ventricular systole

Evolution in a population of island iguanas can be caused by the following agent(s):

All of these can be agents

A group of boys work out and practice for long hours and as a result they become very good at playing basketball. Which of the following statements is true?

All the boys' efforts wont lead to evolutionary change, because their changes lack a genetic basis.

Refer to the figure above. In their investigation of natural selection on Mc1r alleles (the gene that determines coat color) in Arizona pocket mice, Hoekstra et al. determined the frequency of the D and d alleles in each population. They also determined the frequency of alleles for two neutral mitochondrial DNA genes (genes that do not affect and are not linked to coat color). Why did the researchers include the mitochondrial DNA genes as part of their experimental design?

Allele change for the neutral mitochondrial genes serves as a control and gives information on any general background genetic difference among these populations.

How are two different species most likely to evolve from one ancestral species?

Allopatrically, after the ancestral species has split into two populations

Can you think of examples of extreme phenotypes in animal or plant populations that could be explained by directional selection?

Almost any phenotype of an organism that differs markedly from its close relatives is likely the result of directional selection. Among the many thousands of possible examples, consider the long necks of giraffes, the long trucks of elephants, the great body size of whales, the large brain of humans, the great height of giant sequoias, and the large floating leaves of water lilies. Directional selection obviously can result in reduction in size as well, so also consider the tiny body size of hummingbirds compared to other birds, or the tiny leaf size of duck weed compared to other flowering plants. Undoubtedly, you can think of many other examples.

Why doesn't TTX resistance spread throughout the range of the garter snake?

Although TTX resistance is an advantage within the range of the toxic newt, the alleles that confer TTX resistance also lead to slower movement by the snakes (a disadvantage). There is therefore a trade-off in the benefits versus the cost of TTX resistance. In the range of the newt, the advantage outweighs the cost; outside the range of the newt, the cost outweighs the benefit. Thus there is selection for TTX resistance where the snakes occur with the newt, but selection against TTX resistance elsewhere.

Antibiotics are drugs that kill most bacteria, but genetic mutations can allow some individual bacteria to survive short-term exposure to these drugs. How would you expect the frequency of resistant bacteria to change over time in populations of bacteria that were exposed to an antibiotic drug on a regular basis? Why do you think antibiotics come with a warning to take the full course of the treatment, rather than stopping after you begin to feel better?

Although most individual bacteria would die upon exposure to an antibiotic, bacteria that could survive short-term exposure would multiply rapidly after the antibiotic treatment ended. Over time, the population of bacteria would evolve resistance to the antibiotic, as any mutations that allowed survival would increase in frequency. The full treatment is judged to be effective against virtually all the bacteria in the population. If no bacteria survive the full course of the antibiotic, then the population cannot evolve resistance. If the treatment is stopped short, then there is an increased likelihood that some of the bacteria (those with the greatest antibiotic resistance) will survive, and the population of bacteria will evolve increased antibiotic resistance.

How does the mutation rate affect the speed at which the populations become reproductively incompatible?

An increased mutation rate results in more rapid reproductive isolation between the two diverging populations.

Which of the following statements explains why animals are less likely than plants to speciate by polyploidy?

Animals self-fertilize less often than plants, so diploid gametes are less likely to fuse.

Natural selection results in gradual changes within species over long periods of time. Describe an event that could result in significant and sudden changes across many species simultaneously.

Anything that resulted in sudden, widespread environmental change would be likely to affect many species simultaneously. Examples include a meteorite or comet impact, widespread volcanic activity, or sudden climatic changes.

An individual's fitness is determined by its A. ability to compete for limited resources. B. success in contributing genes to future generations. C. ability to escape predators and avoid parasites. D. physical strength and hardiness. E. resistance to disease.

Claytonia virginica is a woodland spring herb with flowers that vary from white to pale pink to bright pink. Slugs prefer to eat pink-flowering over white-flowering plants (due to chemical differences between the two), and plants experiencing severe herbivory are more likely to die. The bees that pollinate this plant also prefer pink to white flowers, so that Claytonia with pink flowers have greater relative fruit set than Claytonia with white flowers. A researcher observes that the percentage of different flower colors remains stable in the study population from year to year. If the researcher removes all slugs from the study population, what do you expect to happen to the distribution of flower colors in the population over time? A. The distribution of flower colors should not change. B. The percentage of pink flowers should increase over time. C. The percentage of white flowers should increase over time. D. The distribution of flower colors should randomly fluctuate over time.

If the frequency of two alleles A and a in a gene pool is 80% and 20%, respectively, what will be the frequency of homozygous dominant individuals in the population? A. 0.80 B. 0.64 C. 0.32 D. 0.16 E. 0.40

Male swallows with the longest tails were found to attract more mates than those with shorter tails. This observation is an example of A. genetic drift, in which tail length increases as a result of small populations. B. intersexual selection in which males with the longest tails are most successful in gaining access to females. C. selection for sexual reproduction, through which high genetic variation is maintained within a population. D. directional selection in which longer tail length increases flying ability and thus ability to forage for food over longer distances

Researchers analyzed rates of twin births in the Sami population of Northern Scandinavia during the eighteenth and nineteenth centuries. They found that (1) a baby born from a singleton pregnancy was more likely to survive to adulthood than a baby born from a twin pregnancy, and (2) the average number of offspring raised to adulthood was higher for women who had twins than for those who never had twins. These data suggest that in this population, human twinning rate was A. under stabilizing selection. B. under directional selection. C. under sexual selection. D. undergoing genetic drift. E. under disruptive selection.

The parasitic flatworms are believed to have evloved from free-living worm forms (non-parasites). The Chinese Liver Fluke infects over half the human population in certain areas of China. The fluke has lost external cilia, has no specialized sense organs, and has a reduced gastrovascular cavity. It absorbs the digested materials of its host. The ancestors of the this fluke had cilia; the Chinese Liver Fluke does not. If the cilia of this particular fluke had not been lost, the structures would now be considered A. divergent. B. vestigial. C. convergent. D. sympatric. E. homologous.

Which of these conditions are always true of populations evolving due to natural selection? Condition 1: The population must vary in traits that are heritable. Condition 2: Some heritable traits must increase reproductive success. Condition 3: Individuals pass on all traits they acquire during their lifetime. A. Conditions 1, 2, & 3 B. Conditions 1 & 2 C. Condition 1 only D. Conditions 2 & 3 E. Condition 2 only

Arctic toothfishes live in very cold water year-round. These fishes express unique genes that code for anti-freeze proteins. The production of anti-freeze proteins in these fish is an example of _____. A. acclimation B. an adaptation C. an acquired characteristic as defined by Lamarck D. genetic correlation

B an adaptation

Which variable increases the likelihood of allopatric speciation taking place more quickly? A. lower rate of mutation B. longer distance between divided groups C. increased instances of hybrid formation D. equivalent numbers of individuals in each population

B longer distances

Which scientific concept did Charles Darwin and Alfred Wallace independently discover? a.mutation b.natural selection c. overbreeding d. sexual reproduction

B natural selection

What is the main difference between dispersal and vicariance? A. One leads to allopatric speciation, whereas the other leads to sympatric speciation. B. One involves the movement of the organism, and the other involves a change in the environment. C. One depends on a genetic mutation occurring, and the other does not. D. One involves closely related organisms, and the other involves only individuals of the same species.

B one involves the movement of the organism (dispersal) and the other a change in the environment (vicariance)

Given a population that contains genetic variation, what is the correct sequence of the following events under the influence of natural selection? 1. Well-adapted individuals leave more offspring than do poorly adapted individuals. 2. A change occurs in the environment. 3. Genetic frequencies within the population change. 4. Poorly adapted individuals have decreased survivorship. A) 4 → 2 → 3 → 1 B) 2 → 4 → 1 → 3 C) 2 → 4 → 3 → 1 D) 4 → 2 → 1 → 3 E) 4 → 1 → 2 → 3

B) 2 → 4 → 1 → 3

5) Rank the following one-base point mutations (from most likely to least likely) with respect to their likelihood of affecting the structure of the corresponding polypeptide. 1. insertion mutation deep within an intron 2. substitution mutation at the third position of an exonic codon 3. substitution mutation at the second position of an exonic codon 4. deletion mutation within the first exon of the gene A) 1, 2, 3, 4 B) 4, 3, 2, 1 C) 2, 1, 4, 3 D) 3, 1, 4, 2

B) 4, 3, 2, 1

3) Which statement about the beak size of finches on the island of Daphne Major during prolonged drought is true? A) Each bird evolved a deeper, stronger beak as the drought persisted. B) Each bird's survival was strongly influenced by the depth and strength of its beak as the drought persisted. C) Each bird that survived the drought produced only offspring with deeper, stronger beaks than seen in the previous generation. D) The frequency of the strong-beak alleles increased in each bird as the drought persisted.

B) Each bird's survival was strongly influenced by the depth and strength of its beak as the drought persisted.

Which of the graphs above best represents the relationship between the intensity of directional selection and the genetic variation present within a population? A) Graph A B) Graph B C) Graph C D) Graph D E) Graph E

B) Graph B

Why is bipedalism considered a synapomorphy for hominins (the group that includes humans)? A) Hominins are sister taxa to the great apes. B) Hominins are the only mammal group to walk on two legs. C) Many mammals are bipedal, but natural selection has caused hominins to share similar traits. D) All primates have two legs.

B) Hominins are the only mammal group to walk on two legs.

Which statement about inbreeding is correct? ANSWER: A) Offspring produced by inbreeding have high biological fitness. B) Inbreeding increases the rate of purifying selection. C) Inbreeding changes allele frequencies in a population. D) Inbreeding increases random mating.

B) Inbreeding increases the rate of purifying selection.

How might gene flow be important in managing an endangered species? A) It increases genetic diversity by introducing new alleles into the DNA of a population. B) It increases genetic diversity by introducing alleles from one population into another. C) It is not important to managing an endangered species. D) It decreases genetic diversity via the loss of alleles due to inbreeding depression.

B) It increases genetic diversity by introducing genes from one population into another.

In 1986, a nuclear power accident in Chernobyl, USSR (now Ukraine), led to high radiation levels for miles surrounding the plant. The high levels of radiation caused elevated mutation rates in the surviving organisms, and evolutionary biologists have been studying rodent populations in the Chernobyl area ever since. Based on your understanding of evolutionary mechanisms, which of the following most likely occurred in the rodent populations following the accident? A) Mutations caused major changes in rodent physiology over time. B) Mutation led to increased genetic variation. C) Mutation caused genetic drift and decreased fitness. D) Mutation caused the fixation of new alleles.

B) Mutation led to increased genetic variation.

Which is strong evidence that similar traits in different evolutionary lineages are the result of homology and not homoplasy? A) The traits are genetic, not morphological. B) The traits are also found in many intervening lineages on the tree of life. C) The traits are not also found in many intervening lineages on the tree of life. D) The traits are analogous.

B) The traits are also found in many intervening lineages on the tree of life.

A hybrid zone is properly defined as _____. A) an area where two closely related speciesʹ ranges overlap. B) an area where mating occurs between members of two closely related species, producing viable offspring. C) a zone that features a gradual change in species composition where two neighboring ecosystems border each other. D) a zone that includes the intermediate portion of a cline. E) an area where members of two closely related species intermingle, but experience no gene flow.

B) an area where mating occurs between members of two closely related species, producing viable offspring.

Most causes of speciation are relatively slow, in that they may take many generations to see changes, with the exception of _____. A) natural selection B) polyploidy C) reinforcement D) colonization

B) polyploidy

Examine the figure above. What type of selection for body size appears to be occurring in these marine iguanas? A) directional selection B) stabilizing selection C) disruptive selection D) You cannot determine the type of selection from the above information.

B) stabilizing selection

Most Swiss starlings produce four to five eggs in each clutch. Starlings producing fewer or more than this have reduced fitness. Which of the following terms best describes this situation? A) directional selection B) stabilizing selection C) disruptive selection D) sexual selection

B) stabilizing selection

The question refers to the following description. In the ocean, on either side of the Isthmus of Panama, are 30 species of snapping shrimp; some are shallow-water species, others are adapted to deep water. There are 15 species on the Pacific side and 15 different species on the Atlantic side. The Isthmus of Panama started rising about 10 million years ago. In the following figure, the isthmus separates the Pacific Ocean on the left (side A) from the Atlantic Ocean on the right (side B). The seawater on either side of the isthmus is separated into five depth habitats (1-5), with 1 being the shallowest. In which habitat should one find snapping shrimp most closely related to shrimp that live in habitat A4? A. A5 B. B4 C. A3 D. either A3 or A5 E. any species from any one of the side A habitats

B. B4

Which statement is the best contemporary definition of evolution? A. Evolution is natural selection in two populations B. Evolution is a change in allele frequencies over time within a population C. Evolution is an example of Mendelian inheritance D. Evolution is the same as Hardy-Weinberg equilibrium

B. Evolution is a change in allele frequencies over time within a population

The same gene that causes various coat patterns in wild and domesticated cats also causes a cross-eyed condition in these cats, the cross-eyed condition being slightly maladaptive. In a hypothetical environment, the coat pattern that is associated with crossed eyes is highly adaptive, with the result that both the coat pattern and the cross-eyed condition increase in a feline population over time. Which statement is supported by these observations? A. Evolution is progressive and tends toward a more perfect population. B. Phenotype is often the result of compromise. C. Natural selection reduces the frequency of maladaptive genes in populations over the course of time. D.Polygenic inheritance is generally maladaptive, and should become less common in future generations.

B. Phenotype is often the result of compromise.

Which event would not result in allopatric speciation? A. an earthquake that isolates a population of rodents on a mountain B. development of different antler sizes between male and female reindeer C. barrier that inhibits gene flow. D. migration of birds to an island E. a flood that separates a population of frogs onto opposite sides of a large lake

B. development of different antler sizes between male and female reindeer

Which of the following evolutionary forces can introduce new genetic variation into a population? A. natural selection and genetic drift B. mutation and gene flow C. natural selection and nonrandom mating D. mutation and genetic drift

B. mutation and gene flow

The figure shows an overview of the experiment described in the tutorial. What do the gray dots on the figure represent?

B.Genetically distinct viruses that are related through a shared evolutionary history

In the following figure, the isthmus separates the Pacific Ocean on the left (side A) from the Atlantic Ocean on the right (side B). The seawater on either side of the isthmus is separated into five depth habitats (1—5), with 1 being the shallowest. An isthmus separates ocean area A on the left from area B on the right with five layered depth habitats. A1 and B1 are just beneath the ocean surface. Habitat layers 2-5 are successively deeper, with A5 and B5 at the bottom (about 100 feet deep). In which habitat should one find snapping shrimp most closely related to shrimp that live in habitat A4?

Why is genetic drift often a factor influencing speciation after a founder event?

Because founder events typically involve small numbers of individuals

Why is it important to consider only homologous characters in constructing phylogenetic trees?

Because homologous characters are similar as a result of their common descent. Similarities that result from convergent evolution (the wings of birds and insects, for example) can be misleading about evolutionary relationships if they are mistaken as homologous characters.

Suppose that the natural ranges of horses and donkeys were to overlap. Which of the following statements best describes what would likely happen to the populations over time?

Because their hybrid offspring are not reproductively fit, reinforcement could strengthen prezygotic barriers.

Which of the types of reproductive barriers listed below corresponds to the following situation: two species of frogs who use different mating calls?

Behavioral Isolation

Natural selection cannot adapt populations to conditions they have not experienced. Yet many organisms appear to respond to natural events before they happen. For example, many mammals go into hibernation while it is still quite warm. Similarly, many birds leave the temperate zone for their southern wintering grounds long before winter has arrived. How do you think such "anticipatory" behaviors evolve?.

Behaviors can respond to environmental cues that are predictive of future conditions, and these behaviors can be selected for if they are under genetic control. For example, day length becomes shorter as we move closer to winter, so individual mammals have a survival advantage if they respond to shortening days by going into hibernation. In this case, the environmental cue (day length) is predictive of future environmental conditions (the cold of winter). The traits exist in the present because these associations (as between shortening day length and the approach of winter) have existed for a long time.

Why do different biologists emphasize different attributes of species in formulating species concepts?

Biologists are interested in many aspects of species, and their emphases differ depending on the questions they are asking about species. Biologists who are interested in the processes that led to lineage-splitting emphasize the mechanisms that allow lineages to diverge and to remain isolated from one another after divergence (i.e., how species come into existence and remain distinct from one another). Biologists who are mostly concerned with identifying species and understanding their distribution in time and space are more likely to emphasize historical aspects and how we can tell species apart (i.e., how we recognize species in nature). Still other biologists may be interested primarily in how species co-exist in communities, and these biologists are likely to emphasize the ecological role of species (how do species differ in their adaptations and niches?). Each of these emphases leads different biologists to emphasize different attributes of species.

What do both rate of speciation models have in common?

Both models continue to conform to the rules of natural selection, and influence of gene flow, genetic drift and mutation

A student states that genetic drift was responsible for genetic divergence of picture-winged Drosophila on the Hawaiian Islands, which led to speciation. Another student states that natural selection was responsible. Evaluate these two statements based on information presented about these flies in the tutorial.

Both students are correct

Which of the following statements regarding the urinary system is TRUE?

Bowman's capsule envelops the glomerulus

Build a canal linking the two ponds that permits free movement of mosquitofish, but not of predators.

Genetic Drift

By chance an allele may be eliminated from a population's gene pool.

For a biologist studying a small fish population in the lab, which Hardy-Weinberg condition is easiest to meet? A. no mutation B. no selection C. no gene flow D. no genetic drift E. random mating

Microevolution is defined as A. new forms replacing old ones. B. the origin of novel designs to survive in new habitats. C. changes in gene frequencies within populations. D. a process that includes episodes of extinction.

The membrane protein that is involved in cystic fibrosis confers resistance to typhoid fever. Imagine that a drug-resistant form of typhoid fever becomes common worldwide, killing a significant proportion of the human population over a period of several decades. Which of the following would you expect to observe in the world population during this period? A. decrease in the frequency of cystic fibrosis B. no change in the frequency of cystic fibrosis C. increase in the frequency of cystic fibrosis

Two populations of birds with somewhat different colorations live on opposite sides of a peninsula. The habitat between the populations is not suitable for these birds. When birds from the two populations are brought together, they produce young whose appearance is intermediate betweent the two parents. These offspring will breed with each other or with birds from either parent population, and all offspring of these pairings appear intermediate to various degrees. What keeps the two populations separate? A. gametic barrier B. behavioral reproductive isolation C. geographic reproductive isolation D. temporal reproductive isolation

Which of the following describes the most likely order of events in speciation? A. genetic isolation, divergence, genetic drift B. divergence, genetic drift, genetic isolation C. genetic isolation, genetic drift, divergence D. divergence, genetic isolation, genetic drift E. genetic drift, genetic isolation, divergence

Which of the following pairs of structures exemplifies homology rather than analogy? A. eyes in spider; eyes in primates B. antenna of insect; barbell ("whisker") of catfish C. flipper of whale; wing of bat D. wing of bird; wing of praying mantis

Which components of speciation would be least likely to be a part of punctuated equilibrium? A. a division of populations B. a change in environmental conditions C. ongoing gene flow among all individuals D. a large number of mutations taking place at once

C a large # of mutation taking place @ once

Which condition is the basis for a species to be reproductively isolated from other members? A. It does not share its habitat with related species. B. It does not exist out of a single habitat. C. It does not exchange genetic information with other species. D. It does not undergo evolutionary changes for a significant period of time.

C it does not exchange genetic info w other species

Which of the following is a requirement for a good scientific hypothesis? A. It must generate quantitative data. B. It must explain a large body of specific observations. C. It must lead to testable predictions. D. It must be proven to be true.

C it must lead to testable predictions

What is the main difference between autopolyploid and allopolyploid? A. the number of chromosomes B. the functionality of the chromosomes C. the source of the extra chromosomes D. the number of mutations in the extra chromosomes

C the source of the extra chromosomes

Which reproductive combination produces hybrids? A. when individuals of the same species in different geographical areas reproduce B. when any two individuals sharing the same habitat reproduce C. when members of closely related species reproduce D. when offspring of the same parents reproduce

C when members of closely related species reproduce

In some jacana species, males take care of the eggs and young, and females compete among themselves for territories that contain one to several males. Female jacanas are significantly larger than males. Which of these statements would you predict to be true of this bird species? 1. Male jacana fitness is primarily limited by ability to take care of eggs and raise young. 2. Female jacana fitness is limited by the number of males in her territory with which a female mates. 3. Variation in reproductive success should be greater in male jacanas than in females. 4. Variation in reproductive success should be greater in female jacanas than in males. 5. Males and females have equal variation in reproductive success. A) 1 and 3 B) 2 and 4 C) 1, 2, and 4 D) 5

C) 1, 2, and 4

Arrange the following in order from most general to most specific. 1 natural selection 2. microevolution 3. intrasexual selection 4. evolution 5. sexual selection A) 4, 1, 2, 3, 5 B) 4, 2, 1, 3, 5 C) 4, 2, 1, 5, 3 D) 1, 4, 2, 5, 3

C) 4, 2, 1, 5, 3

If, on average, 46% of the loci in a species' gene pool are heterozygous, then the average homozygosity of the species should be _____. A) 23% B) 46% C) 54% D) 92%

C) 54%

How do allopatric and sympatric speciation differ? A) Allopatric speciation involves genetic changes as groups form new species; sympatric speciation does not. B) Allopatric speciation involves loss of reproductive compatibility between groups as they form new species; sympatric speciation does not. C) Allopatric speciation involves a physical separation of groups as they form new species; sympatric speciation does not. D) Allopatric speciation involves loss of gene flow between groups; sympatric speciation does not.

C) Allopatric speciation involves a physical separation of groups as they form new species; sympatric speciation does not.

A researcher wants to know if gene flow is contributing to evolution of drought tolerance of pitcher plants in a specific bog. As a control, she should A) Estimate the frequency of alleles relevant genes for drought tolerance. B) Transplant pitcher plants from other populations into the bog. C) Determine if the population is in Hardy-Weinberg equilibrium. D) All of the above. E) None of these. Gene flow does not contribute to evolution.

C) Determine if the population is in Hardy-Weinberg equilibrium.

10) Refer to the accompanying figure. In every case, caterpillars that feed on oak flowers look like oak flowers. In every case, caterpillars that were raised on oak leaves looked like twigs. These results support which of the following hypotheses? A) The longer day lengths of summer trigger the development of twig-like caterpillars. B) Differences in air pressure, due to elevation, trigger the development of different types of caterpillars. C) Differences in diet trigger the development of different types of caterpillars. D) The differences are genetic. A female will either produce all flowerlike caterpillars or all twig-like caterpillars.

C) Differences in diet trigger the development of different types of caterpillars.

Swine are vulnerable to infection by bird flu virus and human flu virus, which can both be present in an individual pig at the same time. When this occurs, it is possible for genes from bird flu virus and human flu virus to be combined. If the human flu virus contributes a gene for Tamiflu resistance (Tamiflu is an antiviral drug) to the new virus, and if the new virus is introduced to an environment lacking Tamiflu, then what is most likely to occur? A) The new virus will maintain its Tamiflu-resistance gene, in case of future exposure to Tamiflu. B) The Tamiflu-resistance gene will undergo mutations that convert it into a gene that has a useful function in this environment. C) If the Tamiflu-resistance gene involves a cost, it will experience directional selection leading to reduction in its frequency. D) If the Tamiflu-resistance gene confers no benefit in the current environment, and has no cost, the virus will increase in frequency.

C) If the Tamiflu-resistance gene involves a cost, it will experience directional selection leading to reduction in its frequency.

Researchers studying a small milkweed population note that some plants produce a toxin and other plants do not. They identify the gene responsible for toxin production. The dominant allele (T) codes for an enzyme that makes the toxin, and the recessive allele (t) codes for a nonfunctional enzyme that cannot produce the toxin. Heterozygotes produce an intermediate amount of toxin. The genotypes of all individuals in the population are determined (see chart) and used to determine the actual allele frequencies in the population. 16) Refer to the figure above. Is this population in Hardy-Weinberg equilibrium? A) Yes. B) No; there are more heterozygotes than expected. C) No; there are more homozygotes than expected. D) More information is needed to answer this question.

C) No; there are more homozygotes than expected.

Which of the following could be a vicariance event for species in that habitat? A) Some insects get blown in a storm to a new mountain range, where they lay eggs. B) Radiation near Chernobyl increases mutation rate, causing an increase in autopolyploidy. C) The level of water in a lake recedes, creating two lakes where there used to be one. D) All of the above could be vicariance events for species in that habitat.

C) The level of water in a lake recedes, creating two lakes where there used to be one.

What is true of the Cambrian explosion? A) The Cambrian explosion marks the appearance of filter-feeding animals in the fossil record. B) Only the fossils of microorganisms are found in geological strata older than the Cambrian explosion. C) There are fossils of animals in geological strata that are older than the Cambrian explosion. D) The Cambrian explosion is evidence for the instantaneous creation of life on Earth.

C) There are fossils of animals in geological strata that are older than the Cambrian explosion.

Which of the following organisms would be most likely to fossilize? A) a rare squirrel B) a common worm C) a common squirrel D) a rare worm

C) a common squirrel

Currently the only predators of Galápagos marine iguanas are Galápagos hawks. Iguana body size is not correlated with risk of hawk predation, although small iguanas can sprint faster than large iguanas. If predators (for example, cats) that preferably catch and eat slower iguanas are introduced to the island, iguana body size is likely to _____ in the absence of other factors; the iguanas would then be under _____ selection. A) increase; directional B) increase; disruptive C) decrease; directional D) decrease; disruptive

C) decrease; directional

A biologist doing a long-term study on a wild spider population observes increased variation in silk thickness. Which of the following could the spider population be experiencing? A) directional selection B) stabilizing selection C) disruptive selection D) genetic drift

C) disruptive selection

Three-spined stickleback fish (Gasterosteus aculeatus) show substantial heritable variation in gill-raker length related to differences in their diets. Longer gill rakers appear to function better for capturing open-water prey, while shorter gill rakers function better for capturing shallow-water prey. Which of the following types of selection is most likely to be found in a large lake (open water in the middle and shallow water around the sides) with a high density of these fish? A) directional selection B) stabilizing selection C) disruptive selection D) sexual selection

C) disruptive selection

12) Cystic fibrosis is a genetic disorder in homozygous recessives that causes death during the teenage years. If 9 in 10,000 newborn babies have the disease, what are the expected frequencies of the dominant (A1) and recessive (A2) alleles according to the Hardy-Weinberg model? A) f(A1) = 0.9997, f(A2) = 0.0003 B) f(A1) = 0.9800, f(A2) = 0.0200 C) f(A1) = 0.9700, f(A2) = 0.0300 D) f(A1) = 0.9604, f(A2) = 0.0392

C) f(A1) = 0.9700, f(A2) = 0.0300

On the Bahamian island of Andros, mosquitofish populations live in various, now-isolated, freshwater ponds that were once united. Currently, some predator-rich ponds have mosquitofish that can swim in short, fast bursts; other predator-poor ponds have mosquitofish that can swim continuously for a long time. When placed together in the same body of water, the two kinds of female mosquitofish exhibit exclusive breeding preferences. 44) If one builds a canal linking a predator-rich pond to a predator-poor pond, then what type(s) of selection should subsequently be most expected among the mosquitofish in the original predator-rich pond, and what type(s) should be most expected among the mosquitofish in the formerly predator-poor pond? A) stabilizing selection; directional selection B) stabilizing selection; stabilizing selection C) less-intense directional selection; more-intense directional selection D) less-intense disruptive selection; more-intense disruptive selection

C) less-intense directional selection; more-intense directional selection

6) Genetic variation _____. A) is created by the direct action of natural selection B) arises in response to changes in the environment C) must be present in a population before natural selection can act upon the population D) tends to be reduced by when diploid organisms produce gametes

C) must be present in a population before natural selection can act upon the population

Which of the following events would best be described as a case of speciation in sympatry? A. A population of lizards is subdivided by a natural barrier and subsequently diverges to form two species that cannot interbreed. B. A new, isolated population of fruit flies is founded by a small group of colonists, who then diverge from the ancestral source population. C. An individual hermaphroditic plant undergoes meiotic failure, producing diploid pollen and ovules; these self-fertilize, germinate, and grow into several fully fertile tetraploid plants. D. Speciation cannot take place in sympatry, only in allopatry where geography poses a barrier to gene flow.

C. An individual hermaphroditic plant undergoes meiotic failure, producing diploid pollen and ovules; these self-fertilize, germinate, and grow into several fully fertile tetraploid plants.

Two groups of lizards that have long been living in allopatry have recently been reintroduced in the wild. When members of opposite groups mate, the hybrids are almost always inviable. Which of the following could be expected to occur over the long term if the populations remain in sympatry A. Hybrids will become prevalent now that the groups are not isolated. B. Gene flow will reunite the groups into a single species. C. Behavioral forms of isolation will develop. D. Hybrid sterility will eventually also develop. E. There is not enough information to decide which of these will happen.

C. Behavioral forms of isolation will develop.

Which of the following ideas would you consider to be common to both Darwin's and Lamarck's ideas about evolution A. Changes in phenotype result from mutation B. Evolution makes organisms more and more complex C. Evolutionary change results from interactions between organisms and their environment D. Change in phenotype results from the constant use or disuse of an anatomical structure E. The fossil record shows that species are fixed

C. Evolutionary change results from interactions between organisms and their environment

When closely related individuals mate with each other, or inbreed, the offspring are often not as fit as the offspring of two unrelated individuals. Why? A. Close relatives are genetically incompatible. B. The DNA of close relatives reacts negatively in the offspring. C. Inbreeding can bring together rare, deleterious mutations that lead to harmful phenotypes. D. Inbreeding causes normally silent alleles to be expressed.

C. Inbreeding can bring together rare, deleterious mutations that lead to harmful phenotypes.

What will happen to the size and shape of beaks in medium ground finches, in the future? A. They will continue to get deeper and wider. B. They will continue to get deeper, but they should eventually begin to get narrower as well. C. It depends on changes in the environment. D. They may fluctuate in size and shape, but they will remain roughly constant over the long term.

C. It depends on changes in the environment.

Which of the following is a true statement concerning genetic variation? A. It is created by the direct action of natural selection. B. It arises in response to changes in the environment. C. It must be present in a population before natural selection can act upon the population. D. It tends to be reduced by the processes involved when diploid organisms produce gametes. E. A population that has a higher average heterozygosity has less genetic variation than one with a lower average heterozygosity.

C. It must be present in a population before natural selection can act upon the population.

Which of the following situations is a result of reproductive isolation caused by differences in timing? A. Males and females within a species are active at different times of day. B. Males and females of one species form lifetime pair bonds, whereas males and females of a closely related species are polygamous. C. Males and females of one species breed in early springtime, whereas males and females of a closely related species breed in early summer. D. Males and females of one species breed in oak trees, while males and females of a closely related species breed in maples.

C. Males and females of one species breed in early springtime, whereas males and females of a closely related species breed in early summer.

What is the difference between micro- and macroevolution? A. Microevolution describes the evolution of small organisms, such as insects, while macroevolution describes the evolution of large organisms, like people and elephants. B. Microevolution describes the evolution of microscopic entities, such as molecules and proteins, while macroevolution describes the evolution of whole organisms. C. Microevolution describes the evolution of organisms in populations, while macroevolution describes the evolution of species over long periods of time. D. Microevolution describes the evolution of organisms over their lifetimes, while macroevolution describes the evolution of organisms over multiple generations.

C. Microevolution describes the evolution of organisms in populations, while macroevolution describes the evolution of species over long periods of time.

Which of the following statements reflect aspects of Charles Lyell's ideas of gradualism and uniformitarianism that were incorporated into Darwin s theory of evolution? A. There is a struggle in populations for survival and reproduction B. Natural selection acts on heritable variation C. Small constant changes accumulated over vast spans of time can produce dramatic results D. Characteristics acquired over the life span of an organism are passed on to the next generation E. Extinction is occurring in many groups of organisms

C. Small constant changes accumulated over vast spans of time can produce dramatic results

Which of the following is the best description of a control for an experiment? A. The control group is kept in an unchanging environment. B. The control is left alone by the experimenters. C. The control group is matched with the experimental group except for the one experimental variable. D. The control group is exposed to only one variable rather than several.

C. The control group is matched with the experimental group except for the one experimental variable.

If a population gradually includes more individuals with a trait that has been subject to natural selection what would we expect to happen to allelic frequencies that govern this trait? A. We would expect allelic frequencies to stay the same B. We would expect genotype frequencies to remain constant C. We would expect changes in allele frequencies D. We would expect all allele frequencies to decrease E.We would expect all allele frequencies to increase

C. We would expect changes in allele frequencies

How are two different species most likely to evolve from one ancestral species? sympatrically, by a point mutation affecting morphology or behavior A. sympatrically, due to extensive inbreeding B. allopatrically, due to extensive inbreeding C. allopatrically, after the ancestral species has split into two populations D. phylogenetically, due to heterozygote advantage in hybrids

C. allopatrically, after the ancestral species has split into two populations

Which of the following attributes has the least effect on the contribution an individual makes to the gene pool of the next generation? A. more efficient at obtaining food B. produces more offspring C. camouflages from predators D. spars for mating privileges

C. camouflages from predators

Which type of selection results in greater genetic variance in a population? A. stabilizing selection B. directional selection C. diversifying selection D. positive frequency-dependent selection

C. diversifying selection

When male lions reach sexual maturity, they leave their group in search of a new pride. This can alter the allele frequencies of the population through which of the following mechanisms? A. natural selection B. genetic drift C. gene flow D. random mating

C. gene flow

Natural selection for traits that keep distinct populations from reproducing with each other is called reinforcement. When is reinforcement beneficial? A. when the environment is changing B. when gene flow is low C. when hybrids have lower fitness than either parent population D. when prezygotic isolating mechanisms are in place E. Reinforcement is beneficial under all of the above conditions

C. when hybrids have lower fitness than either parent population

Male deer of some species have evolved to be greater in size, weight, and muscle development than their female counterparts. These traits are advantageous to the males in competing with one another for mates, but are also advantageous in fending off attacks from predators. Which statement provides the best explanation for why females in these species have not also evolved these characteristics as adaptations to fend off predators?

C.On balance, the costs of these adaptations to female deer are greater than their benefits in helping them survive.

A student comments that constructing phylogenetic trees must be possible for organisms with many shared characteristics such as camels and horses, but not possible for organisms with no obvious shared characteristics such as oak trees and sharks. Which statement provides the best evaluation of the student's thinking?

C.The student's thinking is flawed because oak trees and sharks can be compared using phylogenetic analysis, since all organisms share some basic genetic characteristics.

The tutorial presented the case of garter snakes that had evolved sodium channels resistant to the neurotoxin produced by rough-skinned newts. Which statement below provides an explanation about why this adaptation did not become universally spread throughout all garter snake populations?

C.The trait caused a survival disadvantage as well as a survival advantage.

Male frogs give calls that attract female frogs to approach and mate. Researchers examined mating calls of closely related tree frogs in South America. If reinforcement is occurring, what would you expect if you compare the calls of the two species in zones of sympatry versus zones of allopatry?

Calls would be more different in areas of sympatry.

During a study session about evolution, one of your fellow student's remarks, "The giraffe stretched its neck while reaching for higher leaves; its offspring inherited longer necks as a result." Which statement is most likely to be helpful in correcting this student's misconception?

Characteristics acquired during an organism's life are generally not passed on through genes.

Which of these classifications contain a paraphyletic group?

Classification One (the group Reptilia is paraphyletic if the birds are excluded).

Which of these classifications contains a polyphyletic group?

Classification Three (the group Homotheria is polyphyletic).

Which of these classifications is consistent with the goal of including only monophyletic groups in a biological classification?

Classification Two.

Islands are well known for having many endemic species-species that are unique to that location. What is a likely explanation for this pattern?

Colonizers encounter fewercompetitors on an island, so they can diversify.

A biologist has identified two groups of salamanders with very similar physical features on opposite banks of a river. Which investigative approach would help determine whether the groups are the result of allopatric speciation?

Compare the gene pools of the two populations to see if there are any alleles not shared by both groups

Which of these conditions are always true of populations evolving due to natural selection? Condition 1: The population must vary in traits that are heritable. Condition 2: Some heritable traits must increase reproductive success. Condition 3: Individuals pass on most traits that they acquire during their lifetime.

Conditions 1 and 2

A storm brings two formerly separated populations of beetles together. They look very similar. Under the biological species concept, which of the following would show that the two populations are different species? A. One population breeds in spring, the other in fall. B. Males of the two populations have different flight patterns in courtship. C. When individuals from the two populations mate with each other in the laboratory, the eggs fail to hatch. D. All of the above is correct. E. None of the above is correct.

Bird guides once listed the Myrtle Warbler and Audubon's Warbler as distinct species, but applying the biological species concept, recent books show them as eastern and western forms of a single species, the Yellow-rumped Warbler. Experts must have found that the two kinds of warblers A. are reproductively isolated from each other. B. are allopatric. C. live in the same area. D. successfully interbreed in nature. E. look enough alike to be considered one species

English Peppered Moths evolved different colorings due to A. the darker allele being selected against due to soot on the trees. B. a mutation that occured due to soot collecting on the moths. C. the lighter allele being selected for due to an increase in soot on the trees. D. the darker allele being selected for due to an environmental change.

In a small town in northern Europe, 4% of the population is born with a severe form of cystic fibrosis. What percentage of the town enjoys the selective advantage of the cystic fibrosis gene by being more resistant to typhoid fever (heterozygous) than individuals who are homozygous dominant for the "normal" trait? A. 80% B. 20% C. 16% D. 32% E. 4%

Niles Eldredge and Stephen Jay Gould proposed a new model for evolution that suggests A. evolution does not occur on a large scale. B. evolutionary change is due to the gradual accumulation of small changes over long period of time. C. somatic characteristics acquired by an organism during its lifetime can be transmitted to its offspring. D. evolution occurs in short periods of rapid change followed by long periods of equilibrium. E. all evolution is the result of stabilizing selection.

Which of the following ideas is common to both Darwin and Lamarck's theories of evolution? A. Adapation results from differential reproductive success. B. Adaptation results from the use and disuse of anatomical structures. C. Evolution drives organisms to greater and greater complexity. D. Evolutionary adaptation results from interactions between organisms and their environments. E. The fossil record supports the view that species are fixed.

Which of the following situations will lead to natural selection? A. The seeds of two plants land near each other and one grows larger than the other. B. Two types of fish eat the same kind of food, and one is better able to gather food than the other. C. Male lions compete for the right to mate with females, with only one possible winner. D. all of the above

D all of the above

Which situation is most likely an example of convergent evolution? A. Squid and humans have eyes similar in structure. B. Worms and snakes both move without legs. C. Some bats and birds have wings that allow them to fly D. all of the above

D all of the above

Which description is an example of a phenotype? A. A certain duck has a blue beak . B. A mutation occurred to a flower. c. Most cheetahs live solitary lives. D. both a and c

D both a & c

Which situation is not an example of a prezygotic barrier? A. Two species of turtles breed at different times of the year. B. Two species of flowers attract different pollinators. C. Two species of birds display different mating dances. D. Two species of insects produce infertile offspring.

D two species of insects produce infertile offspring (post zygotic barrier)

In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.2. What is the frequency of individuals that are heterozygous for this allele? A) 0.020 B) 0.04 C) 0.16 D) 0.32

D) 0.32

13) Suppose 64% of a remote mountain village can taste phenylthiocarbamide (PTC) and must, therefore, have at least one copy of the dominant PTC taster allele. If this population conforms to Hardy-Weinberg expectations for this gene, what percentage of the population must be heterozygous for this trait? A) 16% B) 32% C) 40% D) 48%

D) 48%

In the Dobzhansky-Muller model, an ancestral population (aabb) splits into two lineages. Different mutations produce different new alleles in each population (Aabb in one population, aaBb in the other). All of the following genotypes would be viable except

D) AaBb.

4) Which statement about variation is true? A) All phenotypic variation is the result of genotypic variation. B) All genetic variation produces phenotypic variation. C) All nucleotide variability results in neutral variation. D) All new alleles are the result of nucleotide variability.

D) All new alleles are the result of nucleotide variability.

You sample a population of butterflies and find that 56% are heterozygous at a particular locus. What should be the frequency of the recessive allele in this population? A) 0.08 B) 0.09 C) 0.70 D) Allele frequency cannot be determined from this information.

D) Allele frequency cannot be determined from this information.

how might the timing of when fruit falls from a tree be important in sympatric speciation? A) Apple fruit falling earlier is a vicariant event. B) Apple fruits fall at the same time as hawthorn fruits, thereby being sympatric. C) Fruit ripening is important for increased reproductive output. D) Apple fruit drops earlier than hawthorn fruit to reduce the interaction of the fly species in time.

D) Apple fruit drops earlier than hawthorn fruit to reduce the interaction of the fly species in time.

How might genotype frequencies change under directional selection? A) Genotypes that represent both smaller and larger individuals become more prevalent. B) Genotypes that represent moderate-sized individuals become more prevalent. C) Genotypes do not change under directional selection. D) Genotypes that represent larger individuals become more prevalent.

D) Genotypes that represent larger individuals become more prevalent.

According to the figure, would you say that evolution has occurred? A) Yes. The allele frequencies are not equal to 0.5. B) No. The allele frequencies are not equal to 0.5. C) Yes. Evolution occurs with each new generation because of the reassortment of alleles. D) No. The allele frequencies did not change between the two generations.

D) No. The allele frequencies did not change between the two generations.

11) Refer to the accompanying figure. Recall that eggs from the same female were exposed to each of the eight treatments used. This aspect of the experimental design tested which of the following hypotheses? A) The longer day lengths of summer trigger the development of twig-like caterpillars. B) Differences in air pressure, due to elevation, trigger the development of different types of caterpillars. C) Differences in diet trigger the development of different types of caterpillars. D) The differences are genetic. A female will either produce all flowerlike caterpillars or all twig-like caterpillars.

D) The differences are genetic. A female will either produce all flowerlike caterpillars or all twig-like caterpillars.

Members of two different species possess a similar-looking structure that they use in a similar way to perform about the same function. Which of the following would suggest that the relationship more likely represents homology instead of convergent evolution? A) Both species are well adapted to their particular environments. B) The two species live at great distance from each other. C) The structures in adult members of both species are similar in size. D) The two species share many proteins in common, and the nucleotide sequences that code for these proteins are almost identical.

D) The two species share many proteins in common, and the nucleotide sequences that code for these proteins are almost identical.

The figure above shows the distribution of pocket-mouse coat colors in several Arizona populations found either on light-colored granite substrate or on dark volcanic rock (dark substrate). The Melanocortin-1 receptor (Mc1r) alleles, D and d, differ by four amino acids. Mice with DD and Dd genotypes have dark coats, whereas mice with the dd genotype are light colored. What sort of genotype frequencies might you expect to find in the Xmas, Mid, and O'Neill populations? A) Xmas-high DD frequency; Mid-high Dd frequency, O'Neill-high dd frequency B) Xmas-high Dd frequency; Mid-high DD frequency, O'Neill-high dd frequency C) Xmas-high dd frequency; Mid-high Dd frequency, O'Neill-high DD frequency D) Xmas-high dd frequency; Mid-high DD frequency, O'Neill-high Dd frequency

D) Xmas-high dd frequency; Mid-high DD frequency, O'Neill-high Dd frequency

In 1983 a population of dark-eyed junco birds became established on the campus of the University of California, San Diego (UCSD), which is located many miles from the junco's normal habitat in the mixed-coniferous temperate forests in the mountains. Juncos have white outer tail feathers that the males display during aggressive interactions and during courtship displays. Males with more white in their tail are more likely to win aggressive interactions, and females prefer to mate with males with more white in their tails. Females have less white in their tails than do males, and display it less often. (Pamela J. Yeh. 2004. Rapid evolution of a sexually selected trait following population establishment in a novel habitat. Evolution 58[1]:166-74.) Refer to the paragraph on dark-eyed junco birds. The UCSD campus male junco population tails were, on average, 36% white, whereas the tails of males from nearby mountain populations averaged 40-45% white. If this observed trait difference were due to a difference in the original colonizing population, it would most likely be due to _____. A) mutations in the UCSD population B) gene flow between populations C) a genetic bottleneck D) a founder effect E) sexual selection

D) a founder effect

An earthquake decimates a ground-squirrel population, killing 98% of the squirrels. The surviving population happens to have broader stripes, on average, than the initial population. If broadness of stripes is genetically determined, what effect has the ground-squirrel population experienced during the earthquake? A) directional selection B) disruptive selection C) a founder event D) a genetic bottleneck

D) a genetic bottleneck

Which of the following is the most predictable outcome of increased gene flow between two populations? A) lower average fitness in both populations B) higher average fitness in both populations C) increased genetic difference between the two populations D) decreased genetic difference between the two populations

D) decreased genetic difference between the two populations

Which of the following is the best modern definition of evolution? A) survival of the fittest B) inheritance of acquired characters C) change in the number of genes in a population over time D) descent with modification

D) descent with modification

In those parts of equatorial Africa where the malaria parasite is most common, the sickle-cell allele constitutes 20% of the β hemoglobin alleles in the human gene pool. 59) In the United States, the parasite that causes malaria is not present, but African-Americans whose ancestors were from equatorial Africa are present. What should be happening to the sickle-cell allele in the United States, and what should be happening to it in equatorial Africa? A) stabilizing selection; disruptive selection B) disruptive selection; stabilizing selection C) directional selection; disruptive selection D) directional selection; stabilizing selection

D) directional selection; stabilizing selection

The Dunkers are a religious group that moved from Germany to Pennsylvania in the mid-1700s. They do not marry with members outside their own immediate community. Today, the Dunkers are genetically unique and differ in gene frequencies, at many loci, from all other populations including those in their original homeland. Which of the following likely explains the genetic uniqueness of this population? A) population bottleneck and Hardy-Weinberg equilibrium B) heterozygote advantage and stabilizing selection C) mutation and natural selection D) founder effect and genetic drift

D) founder effect and genetic drift

When imbalances occur in the sex ratio of sexual species that have two sexes (that is, other than a 50:50 ratio), the members of the minority sex often receive a greater proportion of care and resources from parents than do the offspring of the majority sex. This is most clearly an example of _____. A) sexual selection B) balancing selection C) stabilizing selection D) frequency-dependent selection

D) frequency-dependent selection

Over time, the movement of people on Earth has steadily increased. This has altered the course of human evolution by increasing _____. A) nonrandom mating B) geographic isolation C) genetic drift D) gene flow

D) gene flow

Which of the following describes the most likely order of events in allopatric speciation? A) genetic drift, genetic isolation, divergence B) divergence, genetic isolation, genetic drift C) genetic isolation, divergence, genetic drift D) genetic isolation, genetic drift, divergence E) divergence, genetic drift, genetic isolation

D) genetic isolation, genetic drift, divergence

21) In the formula for determining a population's genotype frequencies, the "pq" in the term 2pq is necessary because _____. A) the population is diploid B) heterozygotes can come about in two ways C) the population is doubling in number D) heterozygotes have two alleles

D) heterozygotes have two alleles

A proficient engineer can easily design skeletal structures that are more functional than those currently found in the forelimbs of such diverse mammals as horses, whales, and bats. The actual forelimbs of these mammals do not seem to be optimally arranged because _____. A) natural selection has not had sufficient time to create the optimal design in each case, but will do so given enough time B) in many cases, phenotype is determined by genotype and the environment C) though we may not consider the fit between the current skeletal arrangements and their functions excellent, we should not doubt that natural selection ultimately produces the best design D) natural selection is generally limited to modifying structures that were present in previous generations and in previous species

D) natural selection is generally limited to modifying structures that were present in previous generations and in previous species

14) For a biologists studying a large flatworm population in the lab, which Hardy-Weinberg condition is most difficult to meet? A) no selection B) no genetic drift C) no gene flow D) no mutation

D) no mutation

The higher the proportion of loci that are "fixed" in a population, the lower are that population's _____. A) nucleotide variability B) chromosome number C) average heterozygosity D) nucleotide variability and average heterozygosity

D) nucleotide variability and average heterozygosity

Soon after the island of Hawaii rose above the sea surface (somewhat less than one million years ago), the evolution of life on this new island should have been most strongly influenced by _____. A) a genetic bottleneck B) sexual selection C) habitat differentiation D) the founder effect

D) the founder effect

Which of the following evidence most strongly supports the common origin of all life on Earth? All organisms _____. A) reproduce B) evolve C) require energy D) use essentially the same genetic code E) show heritable variation

D) use essentially the same genetic code

In a hypothetical population of tree swallows, 18 individuals are homozygous for the c4 allele, 22 individuals are heterozygous for the allele, and 10 individuals lack the allele. What is the frequency of the c4 allele?

D. 0.58

Male frogs give calls that attract female frogs to approach and mate. Researchers examined mating calls of closely related tree frogs in South America. What outcomes can occur where the ranges of two species overlap? A. A stable hybrid zone will form if hybrids are better adapted to the area of overlap than either parent species is. B. The species will interbreed, eventually fusing over time. C. Species will continue to diverge and be isolated by behavioral or genetic mechanisms. D. All of the above are possible outcomes. E. None of the above is a possible outcome.

D. All of the above are possible outcomes.

Speciation is caused by genetic isolation and genetic divergence. Why is genetic isolation important? A. Isolation makes genetic drift particularly important as an evolutionary force. B. Isolation leads to inbreeding and rapid divergence. C. Isolation is common and can result from any mechanism that reduces gene flow between populations. D. Allele frequencies change independently in isolated populations.

D. Allele frequencies change independently in isolated populations.

The question refers to the following description. On the Bahamian island of Andros, mosquitofish populations live in various, now-isolated, freshwater ponds that were once united. Currently, some predator-rich ponds have mosquitofish that can swim in short, fast bursts; other predator-poor ponds have mosquitofish that can swim continuously for a long time. When placed together in the same body of water, the two kinds of female mosquitofish exhibit exclusive breeding preferences. What is the best way to promote fusion between two related populations of mosquitofish, one of which lives in a predator-rich pond, and the other of which lives in a predator-poor pond? A. Perform a reciprocal transfer of females between predator-rich and predator-poor ponds. B. Transfer only female mosquitofish from a predator-rich pond to a predator-poor pond. C. Remove predators from a predator-rich pond and transfer them to a predator-poor pond. D. Build a canal linking the two ponds that permits free movement of mosquitofish, but not of predators.

D. Build a canal linking the two ponds that permits free movement of mosquitofish, but not of predators.

Identify the statement that describes the imperfection of natural selection. A. Natural selection has not had sufficient time to create the optimal design in each case, but will do so given enough time. B. In many cases, phenotype is not merely determined by genotype, but by the environment as well. C. Though we may not consider the fit between the current skeletal arrangements and their functions excellent, we should not doubt that natural selection ultimately produces the best design. D. Natural selection is generally limited to modifying structures that were present in previous generations and in previous species.

D. Natural selection is generally limited to modifying structures that were present in previous generations and in previous species.

Penguins in Antarctica are superb swimmers, but they walk awkwardly and cannot fly. There is evidence that penguin ancestors could fly long ago. How might natural selection explain this? A. Mutations in the genes for wings caused ancestral penguins to start swimming instead of flying. B. The wings of ancestral penguins shrank because the penguins did not use them. C. Penguins today have wings; they do not use them for flying because they do not need them. Penguins today have no need to fly because they are better at swimming. D. Shorter wings may have helped ancestral penguins survive in their environment by enabling them to swim better, and so genes for shorter wings became common.

D. Shorter wings may have helped ancestral penguins survive in their environment by enabling them to swim better, and so genes for shorter wings became common.

Which of the following would not be a good example of prezygotic reproductive isolation? A. Two bird species live in the same area and, while similar in plumage, engage in dramatically different courtship dances. B. Two beetle species are superficially similar in appearance, but the structure of the male penis and the female genitalia prevents males from one species from copulating with females of the other. C. Two plant species have wind-dispersed pollen that lands on the styles and grows a pollen tube through the ovary of either species; however, in hybrid matings, the sperm cannot fertilize the ovum. D. Two frog species meet and can mate with each other, but the hybrid offspring are infertile

D. Two frog species meet and can mate with each other, but the hybrid offspring are infertile

Which of the following populations is not in Hardy-Weinberg equilibrium? A. a population with 12 homozygous recessive individuals (yy), 8 homozygous dominant individuals (YY), and 4 heterozygous individuals (Yy) B. a population in which the allele frequencies do not change over time C. p2 + 2pq + q2 = 1 D. a population undergoing natural selection

D. a population undergoing natural selection

One of the original Amish colonies rose from a ship of colonists that came from Europe. The ship's captain, who had polydactyly, a rare dominant trait, was one of the original colonists. Today, we see a much higher frequency of polydactyly in the Amish population. This is an example of: A. natural selection B. genetic drift C. founder effect D. b and c

D. b and c

What is a cline? A. the slope of a mountain where a population lives B. the degree to which a mutation helps an individual survive C. the number of individuals in the population D. gradual geographic variation across an ecological gradient

D. gradual geographic variation across an ecological gradient

In science, not popular culture, the term theory, generally applies to an idea that A. is a speculation lacking support, observations or experimental evidence. B. attempts to explain some recently observed phenomena. C. is the same as a hypothesis. D. is generally considered to be a very strongly supported statement about nature. E. is all of the above.

D. is generally considered to be a very strongly supported statement about nature.

The good genes hypothesis is a theory that explains what? A. why more fit individuals are more likely to have more offspring B. why alleles that confer beneficial traits or behaviors are selected for by natural selection C. why some deleterious mutations are maintained in the population D. why individuals of one sex develop impressive ornamental traits

D. why individuals of one sex develop impressive ornamental traits

Suppose the simulation is set to a moth population consisting of 10% black and 90% light gray individuals, and the environmental background undergoes a change from light gray to very dark gray. Which initial outcome do you predict will occur?

D.The total population numbers will decrease, and the percentages will shift to a greater percentage of black individuals and a lesser percentage of light gray individuals.

Which observation prompted Darwin to formulate his ideas on evolution?

Darwin noticed that volcanic islands have endemic species, and that these species are similar to others found on the nearest mainland.

How do the theories of Lamarck and Darwin differ?

Darwin proposed that populations evolove; lamarck proposed that individuals evolve.

9) Refer to the accompanying figure. Which one of the following is NOT a plausible hypothesis to explain the differences in caterpillar appearance observed in this population? A) The longer day lengths of summer trigger the development of twig-like caterpillars. B) The cooler temperatures of spring trigger the development of flowerlike caterpillars. C) Differences in air pressure, due to differences in elevation, trigger the development of different types of caterpillars. D) Differences in diet trigger the development of different types of caterpillars.

Differences in air pressure, due to differences in elevation, trigger the development of different types of caterpillars.

Disruptive Selection

In eusocial insects with the haploid-diploid system (like ants or bees), which group(s) are haploid?

Drones (males)

Which of the following is a correct statement about mutations? A. They drive evolution by creating mutation pressures. B. They are most often beneficial to the organisms in which they occur. C. They occur germ cells (reproductive cells) but not in somatic cells. D. They are only harmful. E. They are a source of variation for evolution.

Of the following which was the prevailing idea regarding the origin of species prior to Darwin? A. All species created independently B. The earth is very young C. Species are incapable of change D. Species could be arranged on a scale or into a hierarchical set of categories E. All of the above

E all of the above

Genetic drift occurs in a population. Which of the following statements might be true? Genetic drift occurs in a population. Which of the following statements might be true? A) Genetic drift decreased the population's fitness. B) The population experiences a decrease in genetic variation. C) The population was relatively small. D) Genetic drift increased the population's fitness. E) Any of the statements can be true.

E) Any of the statements can be true.

Which factor most likely caused animals and plants in India to differ greatly from species in nearby southeast Asia? A) The species have become separated by convergent evolution. B) The climates of the two regions are similar. C) India is in the process of separating from the rest of Asia. D) Life in India was wiped out by ancient volcanic eruptions. E) India was a separate continent until 45 million years ago.

E) India was a separate continent until 45 million years ago.

Upon being formed, oceanic islands, such as the Hawaiian Islands, should feature what characteristic, leading to which phenomenon? A) overcrowding, leading to rafting to nearby lands B) adaptive radiation, leading to founder effect C) major evolutionary innovations, leading to rafting to nearby continents D) mass extinctions, leading to bottleneck effect E) a variety of empty ecological niches, leading to adaptive radiation

E) a variety of empty ecological niches, leading to adaptive radiation

The question refers to the following description. On the Bahamian island of Andros, mosquitofish populations live in various, now-isolated, freshwater ponds that were once united. Currently, some predator-rich ponds have mosquitofish that can swim in short, fast bursts; other predator-poor ponds have mosquitofish that can swim continuously for a long time. When placed together in the same body of water, the two kinds of female mosquitofish exhibit exclusive breeding preferences. Which two of the following have operated to increase divergence between mosquitofish populations on Andros? 1. improved gene flow 2. bottleneck effect 3. sexual selection 4. founder effect 5. natural selection A. 3 and 4 B. 2 and 4 C. 2 and 3 D. 1 and 3 E. 3 and 5

E. 3 and 5

The beak size of Geospiza fortis (the medium ground finch) was found to fluctuate as a result of which of the following? A. The amount of rainfall on the island B. The size of available seeds on the island C. The non-random survival of finches on the island D. None of the above E. All of the above

E. All of the above

According to the theory of evolution by natural selection A. survival and reproduction are random. B. species do not go extinct. C. organisms will always increase in complexity. D. the fittest always survive E. non random reproduction and survival occurs in populations.

E. non random reproduction and survival occurs in populations.

Which of the following statements best summarizes evolution by natural selection as it is viewed today?

Evolution by natural selection is the differential survival and reproduction of the most-fit phenotypes.

During the 1977 drought on the island of Daphne Major, medium ground finches did not reproduce and 84% of the birds died. Did evolution occur at this time?

Evolution occured although there was no reproduction because mortality was not random

Which of the following is NOTa main goal of population genetics?

Explaining how genotypic information is expressed as phenotypic traits

In a small population of alpine foxes, you observe increased ear length over a 10-year period. Based on this information you cab conclude that increase in ear length is advantageous in this population.

False

What factor(s) contribute to genetic divergence between two geographically isolated populations?

Genetic drift, natural selection, and the appearance of different mutations in the two populations

Which sequence of events is most likely in allopatric isolation?

Geographic barrier, genetic divergence, reproductive isolation

How could the presence of a great deal of genetic variation within a population increase the chances that some members of the population would survive an unprecedented environmental change? Why is there no guarantee that this would be the case?

High genetic variation leads to more opportunities for the presence of beneficial alleles or traits. If the environment suddenly changes, and beneficial traits are already present in the population, then selection can increase the frequency of those traits and the population can rapidly evolve. However, high genetic variation does not guarantee that appropriate beneficial alleles will already be present in the population.

Structures as different as human arms, bat wings, and dolphin flippers contain many of the same bones, which develop from similar embryonic tissues. These structural similarities are an example of _____.

Homology

Resistance to a wide variety of insecticides, fungicides, antibiotics, antiviral drugs, and herbicides has recently evolved in hundreds of insects, fungi, bacteria, viruses, and plants. Why?

Humans are altering the environments of these organisms, and populations of these organisms are evolving by natural selection.

In what ways does selection by humans in developing agricultural crops differ from natural selection? Can you give an example of a trait that might be favored by artificial selection in agriculture, but selected against by natural selection in a wild population?

Humans select traits in domestic plant and animal populations based on our interest in the trait, rather than on how it affects the natural reproductive rate or survivorship of the organisms. Many of the traits selected by humans would not be advantageous in wild populations. For example, humans have selected many cattle breeds for high body fat and high body weight. These traits result in large calves, which in turn result in calving difficulties for cows. Ranchers often have to assist in the birth of such calves, because the calf (and likely its mother) would often die without such assistance. In a natural population, there would be selection for smaller calf size and birth weight, which would increase the successful reproductive rate and survivorship.

Which is least likely to evolve via direct natural selection?

Hybrid infertility

Suppose the allopatric populations of D. serrata were taken into the lab and exposed to D. birchii for many generations. If the artificial selection in this experiment acted like the natural selection in reinforcement, what would you expect to happen to the concentrations of each of the hydrocarbons in the allopatric populations?

Hydrocarbon 2 in the allopatric populations of D. serrata would be expected to evolve to be more like the sympatric populations and less like D. birchii. Thus, its concentration would be expected to decrease in the lab populations. The concentrations of the other hydrocarbons would be expected to remain about the same, as they do not appear to be undergoing reinforcement.

Based on the data, which hydrocarbon(s) show a pattern that is consistent with reinforcement? Explain your answer.

Hydrocarbon 2 shows a pattern consistent with reinforcement. Under reinforcement, the difference between the sympatric populations and the other species should be greater than the difference between the allopatric populations and the other species. This pattern is observed only for hydrocarbon 2.

Which of the following statements best distinguishes hypotheses from theories in science? A. Theories are hypotheses that have been proved. B. Hypotheses are guesses; theories are correct answers. c. Hypotheses usually are relatively narrow in scope; theories have broad explanatory power. D. Theories are proved true; hypotheses are often contradicted by experimental results.

Hypotheses usually are relatively narrow in scope; theories have broad explanatory power

Fly species W, found in a certain part of the island, produces fertile offspring with species Y. Species W does not produce fertile offspring with species X or Z. If no other species can hybridize, then which of the following statements about species W and Y is/are TRUE? I. Species W and Y have genomes that are still similar enough for successful meiosis to occur in hybrid flies. II. Species W and Y have more genetic similarity with each other than either did with the other two species. III. Species W and Y may fuse into a single species if their hybrids remain fertile over the course of many generations.

I, II, and III are correct.

How might you interpret the circled part of the following phylogenetic tree?

I, III and IV an adaptiveradiation,rapid speciation, unknown evolutionary relationships

How can pollinator specialization in plants and sexual selection in animals increase rates of speciation?

If a pollinator specializes on one particular flower type, that will reduce opportunities for cross-fertilization among different flower types. Any polymorphism in flowers can thus lead to rapid genetic divergence between individuals that express each flower type. A similar process occurs with sexual selection in animals. If some females prefer to mate with males that have a certain trait and other females prefer a different male trait, then the population can quickly lead to genetic isolation and differentiation in the two groups.

Two populations that were once isolated come into contact. Which of the following statements about what might happen after contact is false?

If hybrids are unfit, reinforcement of prezygotic barriers would be disfavored.

What hypothetical phylogenetic results could have exonerated the physician?

If the HIV sequences from the victim had been found to be more closely related to those of any other HIV-positive individuals in the local community than they were to those of the physician's patient, then the phylogeny would be inconsistent with the alleged crime, and the results could have been used to exonerate the physician.

Why might selection for a trait in a population shift from directional to stabilizing selection over time, even if the optimal value for the trait stays constant?

If the mean value of a trait in a population is below the optimal value for that trait, then the mean will evolve to be closer to the optimum through directional selection. But, as the population mean reaches the optimum, then the population will experience stabilizing selection (with selection against individuals that are both below and above the population mean).

Why is genetic incompatibility between two alleles at the same locus considered less likely?

If the only difference between the diverging lineages is at a single locus, then both of the new alleles must be functional when they interact with the products of other gene loci (in both lineages). Any genetic incompatibility produced by these new alleles would be expected to affect the parental lineages as well. There are much greater numbers of possible incompatibilities across different gene loci. Rather than two deleterious changes at the same locus (one in each lineage), the Dobzhansky-Muller model allows neutral changes at any pair of loci whose products interact. It is the negative interaction of these products in the hybrid between the two lineages that results in genetic incompatibility.

What do you notice happens to the frequency of allels in larger populations

In relatively large populations, the frequencies of the alleles remain relatively constant. As the population size gets smaller, the chance of an allele becoming fixed or lost is more likely.

What do you notice happens to the frequency of alleles in small populations over many generations?

In very small populations, genetic drift can lead to the fixation or loss of one allele (towards a frequency of 1.0 or 0.0). Alleles take less time to go to fixation (or become lost) in smaller populations.

What was the purpose of including an outgroup made up of individuals that were outside the epidemiological cluster?

Inclusion of viruses from outside the epidemiological cluster also tests the hypothesis that all viral sequences in this cluster are derived from a single ancestral virus. The outgroup was needed to root the tree, which in this case identifies the direction of the transmission of events.

Which is a key element of the Dobzhansky-Muller model of speciation, in which two lineages diverge from a single lineage?

Incompatible alleles at different loci become fixed in the two lineages

Wikelski and Romero (2003) studied large marine iguanas and found that they had higher reproductive success than smaller iguanas did. However, the large iguanas were generally in poor body condition because they could not eat enough; at higher temperatures, their foraging efficiency improved, allowing them to eat more. Thus, Wikelski and Romero hypothesized that iguana size will ________ as global warming gradually increases air and water temperatures in the Galápagos Islands.

Increase

The largest living adult insects weigh less than 75 g (less than the weight of a relatively small songbird, such as a starling). Many flying birds are much larger than any insect, so clearly flight alone does not constrain the current size of insects. Formulate a hypothesis for why there are no giant insects presently roaming Earth.

Insects may be physiologically constrained by their system of respiration, which may not be able to support as large a body as that of birds. This is an example of an historical constraint that limits insect body size.

Which of the following concerning action potentials is FALSE?

Intensity of an action potential can change

Why doesn't inbreeding depression, by itself, cause evolution?

It does not change the population's allele frequencies.

A study showed that the mortality risk for human babies goes up as birth weight decreases below the average. Another study shows an increase in mortality risk as birth weight increases above the average. What can be said about human birth weight?

It is a trait that is shaped by stabilizing selection.

What must be TRUE of any organ described as vestigial?

It must be homologous to some feature in an ancestor.

What must be true of any organ described as vestigial?

It must be homologous to some feature in an ancestor.

In the mid-1900s, the Soviet geneticist Lysenko believed that his winter wheat plants, exposed to increasingly colder temperatures, would eventually give rise to more cold-tolerant winter wheat. Lysenko's attempts in this regard were most in agreement with the ideas of _____.

Lamarck

BottleNeck Effect

Loss of genetic variation due to inbreeding in populations with decreasing numbers.

The restriction enzymes of bacteria protect the bacteria from successful attack by bacteriophages, whose genomes can be degraded by the restriction enzymes. The bacterial genomes are not vulnerable to these restriction enzymes because bacterial DNA is methylated. This situation selects for bacteriophages whose genomes are also methylated. As new strains of resistant bacteriophages become more prevalent, this in turn selects for bacteria whose genomes are not methylated and whose restriction enzymes instead degrade methylated DNA. Over the course of evolutionary time, what should occur? A) Methylated DNA should become fixed in the gene pools of bacterial species. B) Nonmethylated DNA should become fixed in the gene pools of bacteriophages. C) Methylated DNA should become fixed in the gene pools of bacteriophages. D) Methylated and nonmethylated strains should be maintained among both bacteria and bacteriophages, with ratios that vary over time.

Methylated and nonmethylated strains should be maintained among both bacteria and bacteriophages, with ratios that vary over time.

Suppose genetic drift had occurred in some of the populations in the simulation. Which condition would most likely have been present in these cases?

Moth population numbers declined severely due to poor match of their coloration to the environmental background.

In 1986 a nuclear power accident in Chernobyl, USSR, led to high radiation levels for miles surrounding the plant. The high levels of radiation caused elevated mutation rates in the surviving organisms, and evolutionary biologiests have been studying rodent populations in the Chernobyl area ever since. Based on your understanding of evolutionary mechanisms, which of the following most likesly occurred in the rodent populations following the accident?

Mutation led to increased genetic variation

What is true of natural selection?

Mutations occur at random; natural selection can preserve and distribute beneficial mutations

How is mutation a necessary component of the evolutionary processes?

Mutations provide the genetic variation on which all the other evolutionary processes act.

As more humans live longer, many people face degenerative conditions such as Alzheimer's disease that (in most cases) are linked to advancing age. Assuming that some individuals may be genetically predisposed to successfully combat these conditions, is it likely that natural selection alone would act to favor such a predisposition in human populations? Why or why not?

Natural selection cannot act when there is no effect on the effective reproductive rate of the organism. Diseases such as Alzheimer's usually occur long after the reproductive years have passed. As long as the disease does not affect the relative likelihood of the survival of the affected person's offspring (as a result of reduced parental care, for example), we would not expect natural selection to lead to any reduction in Alzheimer's disease in human populations.

which process was responsible for the initial changes in gene frequencies of the moths, and why?

Natural selection, because body coloration determined moth susceptibility to predation

What was the position occupied by Charles Darwin on the voyage of the HMS Beagle?

Naturalist

What kind of traits would be more likely to evolve by genetic drift than by natural selection?

Neutral traits (traits that confer neither an advantage nor a disadvantage) are free to increase or decrease in a populations by drift alone. In small populations, chance effects have a large role. If the difference in fitness between individuals is relatively small, and there are few individuals in a population, then which individuals survive and reproduce is likely to be a result of factors that do not relate directly to the fitness of the organism. Under these conditions, even some mildly deleterious traits are expected to become fixed in the population over short periods of time.

Should the two forms of moths be considered separate species?

For a biologist studying a small fish population in the lab, which Hardy—Weinberg condition is the most EASY to meet?

No gene flow

Are there any homoplasies in your reconstructed phylogeny?

No, because each trait can be placed along a single branch in the tree.

During saltatory conduction, electrical charges are changed at specific locations along an axon. These regions that lack myelin are called

Nodes of Ranvier

Vestigial traits and neutral changes in DNA sequences are good examples of ________.

Non-Adaptive Traits

Natural selection acts directly _________.

On the Phenotype

Why would gene duplication events, such as those seen in the Hoxgene complex, set the stage for adaptive radiation?

One copy of a gene can perform the original function while other copies are available to take on new functions.

HIV's genome of RNA includes the code for reverse transcriptase (RT), an enzyme that acts early in infection to synthesize a DNA genome off of an RNA template. The HIV genome also codes for protease (PR), an enzyme that acts later in infection by cutting long viral polyproteins into smaller, functional proteins. Both RT and PR represent potential targets for antiretroviral drugs. Drugs called nucleoside analogs (NA) act against RT, whereas drugs called protease inhibitors (PI) act against PR. 8) Every HIV particle contains two RNA molecules. If two genes from one RNA molecule become detached and then, as a unit, get attached to one end of the other RNA molecule within a single HIV particle, which of these is true? A) There are now fewer genes within the viral particle. B) There are now more genes within the viral particle. C) A point substitution mutation has occurred in the retroviral genome. D) One of the RNA molecules has experienced gene duplication as the result of translocation.

One of the RNA molecules has experienced gene duplication as the result of translocation.

Identify the false statement below.

Photosynthesis first evolvedless than one billion year ago.

What biological processes are represented in a phylogenetic tree?

Phylogenetic trees can represent any process in which biological lineages diverge, such as speciation (in which case the tree will depict the evolutionary relationships among species), viral replication (in which case the tree will depict the evolutionary relationships among different viral lineages), or gene duplication (in which case the tree will depict the evolutionary relationships among genes). In most cases in this book, phylogenetic trees are used to depict the evolutionary relationships among species or higher groups of organisms.

Why is speciation by polyploidy more likely in plants than in animals?

Plant gametes can be produced by meiosis from somatic cells that have undergone many rounds of mitosis.

Which of the following mating strategies can result in complex penis and vaginal structures for internal mate selection?

Polyandry

Explain how speciation via polyploidy can happen in only two generations.

Polyploids (e.g., tetraploids) can be produced in the first generation. Hybrids between diploids and tetraploids may be produced in the second generation, forming triploid individuals, but meiosis in the triploids results in gametes with unbalanced chromosome numbers, which results in sterile offspring. An F1 tetraploid is able to self-fertilize or mate with another tetraploid and produce fertile offspring. Thus, the polyploidy organism is reproductively isolated from the diploid species, making it a different species.

Most causes of speciation are relatively slow, in that they may take many generations of organism to see changes, except _____. Polyploidy natural selection Vicariance colonization

Polyploidy

Which of the following represents an idea that Darwin learned from the writings of Thomas Malthus?

Populations tend to increase at a faster rate than their food supply normally allows.

The common edible frog of Europe is a hybrid between two species, Rana lessonae and Rana ridibunda. The hybrids were first described in 1758 and have a wide distribution, from France across central Europe to Russia. Both male and female hybrids exist, but when the hybrids mate with other hybrids or with adults of either species, they are rarely successful in producing offspring. What can you infer from this information?

Postzygotic isolation exists between the two frog species.

Assume that the observed frequency of the genotype Aa in the toad population in Question 2 is 0.15, rather than the expected frequency you calculated. What are some possible explanations?

Presumably, the observed population is large enough to calculate that the low frequency of heterozygotes is significant. However, if the present generation of toads was produced by a small number of parents in the previous generation, then random effects of a small population size could explain the observed pattern.

Which term is used to describe the continued divergence of species based on the low fitness of hybrid offspring? reinforcement fusion stability punctuated equilibrium

Reinforcement

Logically, which of these should cast the most doubt on the relationships depicted by an evolutionary tree?

Relationships between DNA sequences among the species did not match relationships between skeletal Patterns.

Logically, which of these should cast the most doubt on the relationships depicted by an evolutionary tree?

Relationships between DNA sequences among the species did not match relationships between skeletal patterns.

Which would be expected to lead to allopatric speciation?

Seeds of a plant native to Australia are carried to Japan, where they are dispersed into the wild

Why do some combinations of chromosomal centric fusions cause problems in meiosis?

Segregation doesn't occur normally, because chromosome arms are linked differently on the different species, resulting in duplications and deletions in meiosis. If two different fusions of chromosomes occur in two different lineages, then the resulting chromosomes cannot pair normally in meiosis in the hybrids.

What are some reasons that similar traits might arise independently in species that are only distantly related? Can you think of examples among familiar organisms? How do biologists account for these homoplasies in reconstructing phylogenies?

Selection for similar environmental conditions often leads to convergence in traits. For example, fish and dolphins both have fins and are similar in body shape because there is strong selection for these traits in an aquatic environment. But these traits have evolved independently in the two groups. Biologists can usually detect such homoplasies because they conflict with a large number of homologous traits in the groups that are similar as a result of their recent shared ancestry. Biologists can minimize homoplasies using the principle of parsimony.

Describe conditions where nonrandom mating does and does not lead to evolution.

Self-fertilization reduces the frequency of heterozygotes but does not change the allele frequencies in a population. By contrast, sexual selection (nonrandom mating in preference for a particular phenotype) produces a directional change in the population. Hence, the population evolves.

Which one of the following statements is FALSE?

Sensory neurons convey signals form the CNS to sensory receptors

What makes reproductive isolation such an important component of each of the species concepts discussed here?

Sexual lineages must have a substantial degree of reproductive isolation or they cannot remain distinct from one another. So even if a biologist is primarily using a morphological species concept, the morphological differences between species cannot be maintained in time and space unless the two species are largely reproductively isolated from each other. Obviously, reproductive isolation is central to the biological species concept. The many versions of lineage species concepts conceptualize species as distinct lineages in the tree of life. If these lineages are to remain distinct from one another through time, they must be substantially reproductively isolated from one another. Thus, reproductive isolation is important (either directly or indirectly) to all of the various species concepts.

Which of the following statements best describes the rationale for applying the principle of parsimony in constructing phylogenetic trees?

Similarity due to common ancestry should be more common than similarity due to convergent evolution.

Parasitic species tend to have simple morphologies. Which of the following statements best explains this observation?

Simple morphologies convey some advantage in most parasites.

Parasitic species tend to have simple morphologies. Which of the following statements best explains this observation?

Simple morphologies convey some advantages in most parasites.

Which of the following modes of selection leads to a reduction in variation but no change in the mean?

Stabilizing selection

The same basic internal organs (kidneys, stomach, heart, lungs) are found in frogs, birds, snakes, and rodents. This is primarily an example of ________.

Structural Homology

Use the phylogenetic tree of West Nile virus isolates shown below to construct a hypothesis about the origin of the virus lineage that was introduced into the United States. The isolates are identified by their place and date of isolation.

The West Nile Virus in the United States appears to be most closely related to a strain of the virus isolated in Israel. A reasonable hypothesis is that the virus emerged in Africa in the 1930s and subsequently moved into Asia and Europe, probably multiple times. In the late 1990s, a strain of the virus from Israel appears to have been transported to New York, perhaps carried by mosquitoes on an airplane or in a cargo shipment. Once in the United States, the virus spread quickly in native bird populations across North America.

How would you expect the rate of speciation of an allopatric case to compare to the rate of speciation of a sympatric case involving formation of allopolyploid offspring?

The allopatric case would occur at a much slower rate than the sympatric case involving allopolyploid offspring.

Why is the biological species concept not applicable to asexually reproducing organisms? Do you think this limits its applicability?

The biological species concept limits its scope to "actually or potentially interbreeding natural populations." Clearly, asexual organisms do not form such populations. Nonetheless, they do form lineages that exist in time and space, and these lineages may be maintained by other factors, such as available niche space. Most biologists who emphasize the biological species concept are interested primarily in the mechanisms that lead to reproductive isolation and its maintenance over time. The lineage concepts of species are not in conflict with the biological species concept, but they represent a more inclusive way to think about all species, regardless of their sexuality. The lineage concepts also allow biologists to study species across geological time (where reproductive interactions are not possible).

Suppose that within a particular moth species, male moths are brightly colored and female moths have a dull coloration. Suppose also that the bright coloration of the males makes them more successful in attracting female mates. Which outcome of this simulation would you predict if the females matched the background well and the males matched the background poorly?

The bright coloration trait in males will persist in future populations because it has a beneficial effect on the population.

Why was the common garden experiment needed? How would the conclusions of the study have been different if the observed differences in the wild populations were not also evident in the lizards raised in a common, controlled environment?

The common garden experiment confirms that the observed differences have a genetic basis, and are not due to different expression of the same genes on the two sets of islands. If the lizards raised in the common garden experiment had not shown the same level of differences that were observed in the wild populations, then the observed changes could not be attributed to evolution, which refers to genetic changes in populations over time.

Which of the following statements concerning resting potential is INCORRECT?

The concentration of sodium is much higher inside the cell than outside the cell

Male birds in a population show a distribution of feather colors from dull to bright red. A biologist kept track of the numbers of males in three categories of feather color over seven generations, as shown in the table. Which of the following conclusions isconsistent with the data?

The data provide evidence of disruptive selection.

The Founder Effect

The establishment of a new and genetically unique population when a few members of a population migrate and form a new colony.

Adaptive Radiation

The evolution of several species from a single species, each occupying a different niche.

What would be the expected branch length from the common ancestor of an HIV isolate from 1970?

The expected branch length would be about 0.09 substitutions per nucleotide.

Plants that produce seeds are known as seed plants. What is the sister group to the seed plants among these taxa?

The fern.

A dam is built that separates a river into two sections—a deep upstream section and a shallow downstream section. When the dam is first built, a fish species is able to move from the upstream section into the downstream section, but not vice versa. Predators can more easily catch the fish in the shallow downstream section than they can in the deep upstream section. Which scenario is most likely to lead to speciation?

The fish population contains individuals with effective predation evasive traits and eventual changes to the dam prevent fish from moving downstream.

What is allopatric speciation?

The formation of new species in populations that are geographically isolated from one another.

Suppose that a group of male pied flycatchers migrated from a region where there were no collared flycatchers to a region where both species were present. Assuming events like this are very rare, which of the following scenarios is LEAST likely?

The frequency of hybrid offspring would increase.

If the artificial selection did act like the natural selection involved in reinforcement, would you expect the frequency of hybridization between allopatric populations and D. birchii to increase or decrease? Why?

The frequency of hybridization should decrease. The artificial selection is operating on the hydrocarbon because hybridization with the other species is disfavored. As a result, fewer hybridizations should take place.

After the retreat of the glaciers, why did the fish species in the Ozarks and Ouachitas remain reproductively isolated from those in the Appalachians to the east?

The glaciers eliminated most of the highlands that formerly connected the two areas, so there is now little appropriate habitat that would allow the differentiated species to interact. But if the interactions were possible, it is likely that the hybrids would exhibit reduced fitness (as explained by the Dobzhansky-Muller model), and there would be selection for prezygotic isolating mechanisms that would minimize hybridization.

Anopheles mosquitoes, which carry the malaria parasite, cannot live above elevations of 5900 feet. In addition, oxygen availability decreases with higher altitude. Consider a hypothetical human population that is adapted to life on the slopes of Mt. Kilimanjaro in Tanzania, a country in equatorial Africa. Mt. Kilimanjaro's base is about 2600 feet above sea level and its peak is 19,341 feet above sea level. If the incidence of the sickle-cell allele in the population is plotted against altitude (feet above sea level), which of the following distributions is most likely, assuming little migration of people up or down the mountain?

The graph that shows a downard projection line

Formulate a hypothesis that explains how this deleterious allele could be maintained in the population, even though individuals who are homozygous for the sickle allele are strongly disadvantaged.

The heterozygotes between the sickle-cell and normal alleles may have an advantage in defense against malaria. The normal allele may be able to function normally, whereas the sickle-cell allele provides protection against the malaria parasite.

A populaiton of 1000 birds exists on a small Pacific island. Some of the birds are yellow, a characteristic determinded by recessive allele. The others are green, a characteristic determined by a dominant allele. A hurricane kills most of the birds on this island and in this population. Only ten birds from this population remain and those birds all have yellow feathers which of the following statements is TRUE?

The hurrican has caused a population bottleneck

Convergent Evolution

The independent development of similarities between unrelated groups resulting from adaptation to similar environments.

Which ofthefollowing statements is false given this phylogeny.

The lack of true leaves in Clubmoss and Psilotum is a homologous character.

Pea aphids (Acyrthosiphon pisum) are the only animals able to synthesize their own carotenoid pigments, due to lateral gene transfer from the genome of a fungus to the genome of a recent ancestor of the pea aphids. The resulting red or green coloration alters the risk the aphids face from specific predators and parasites. Select the correct statement below.

The lateral transfer of genes for carotenoid synthesis from a fungus to an aphid is a form of mutation.

Would you expect the extent of postzygotic reproductive isolation to change as a result of the artificial selection in the experimental evolution study? Explain.

The level of postzygotic reproductive isolation should not change, as postzygotic isolation generally does not evolve via direct selection.

Which of the following could be a vicariance event?

The level of water in a lake recedes, creating two lakes where there used to be one

Which evolutionary process or processes are most likely to explain the observed evolutionary changes? Which processes do you think are less important, and why?

The most important evolutionary process in this example is selection. Given that tree-top Anolis typically have larger toepads compared to ground-dwelling species, it is logical that lizards with larger toepads and more lamellae are more likely to survive and reproduce in tree tops (compared to lizards with smaller toepads and fewer lamellae). By living longer, lizards with larger toepads will produce more offspring over time, and so their genes will be increasingly represented in subsequent generations.

Which of the following statements about the autonomic nervous system divisions is CORRECT?

The parasympathetic and sympathetic nervous systems work antagonistically to maintain homeostasis

The following question is based on information from Frank M. Frey, "Opposing Natural Selection from Herbivores and Pathogens May Maintain Floral-Color Variation in Claytonia virginica (Portulacaceae)," Evolution 58(11), 2004: 2426—37. Claytonia virginica is a woodland spring herb with flowers that vary from white to pale pink to bright pink. Slugs prefer to eat pink-flowering over white-flowering plants (due to chemical differences between the two), and plants experiencing severe herbivory are more likely to die. The bees that pollinate this plant also prefer pink to white flowers, so Claytonia with pink flowers have greater relative fruit set than Claytonia with white flowers. A researcher observes that the percentage of different flower colors remains stable in the study population from year to year. Given no other information, if the researcher removes all slugs from the study population, what do you expect to happen to the distribution of flower colors in the population over time?

The percentage of pink flowers should increase over time.

What did the simulation demonstrate about the rate at which geographically isolated subsets of a population become reproductively incompatible?

The rate increases as the rate of genetic change increases in both subsets.

Researchers examined the molecular divergence of a mitochondrial DNA gene (cyt b) among sister species of birds called honeycreepers on different Hawaiian Islands. They then plotted the measured molecular divergence against the estimated dates for separation of the islands (see below). Calculate the average rate of change in cyt b (the molecular clock) from the graph.

The rate of divergence is represented by the slope of the regression line. Since the regression line goes approximately through the origin (0, 0), the slope is approximately 7.5% change in cyt b per 4 my, or 1.875% change per million years.

Two frog populations (same species) living in two neighboring lakes sing slightly different courtship songs. Increased irrigation makes the land between the two lakes wetter, allowing frogs to expand their ranges to the area between the lakes. Females in both populations prefer loud frogs to quieter frogs but do not distinguish between the two slightly different songs. Assuming that courtship song differences have a genetic basis, predict what will likely happen to the songs of the two frog populations.

The songs will become more similar to each other.

Two researchers experimentally formed tetraploid frogs by fertilizing diploid eggs from Rana porosa brevipoda with diploid sperm from Rana nigromaculata. When they mated these tetraploid frogs with each other, most of the offspring that survived to maturity were tetraploid, with chromosome sets of both diploid parent species. Based on these results, if this type of tetraploid formed in the wild, what would be the result?

The tetraploids would be reproductively isolated from both parent species.

In order for natural selection to change a trait within a population, what must be true about the trait?

The trait must have a genetic basis.

Bird guides once listed the myrtle warbler and Audubon's warbler as distinct species. Recently, these birds have been classified as eastern and western forms of a single species, the yellow-rumped warbler. Which of the following pieces of evidence, if TRUE, would be cause for this reclassification?

The two forms interbreed often in nature, and their offspring have good survival and reproduction.

A large population of laboratory animals has been allowed to breed randomly for a number of generations. After several generations, 25% of the animals display a recessive trait (aa), the same percentage as at the beginning of the breeding program. The rest of the animals show the dominant phenotype, with heterozygotes indistinguishable from the homozygous dominants. 27) What is the most reasonable conclusion that can be drawn from the fact that the frequency of the recessive trait (aa) has not changed over time? A) The two phenotypes are about equally adaptive under laboratory conditions. B) The genotype AA is lethal. C) There has been a high rate of mutation of allele A to allele a. D) There has been sexual selection favoring allele a.

The two phenotypes are about equally adaptive under laboratory conditions.

The two species share many proteins in common, and the nucleotide sequences that code for these proteins are almost identical.

Why is the tree inconsistent with any of the other individuals being the source of infection within this cluster?

The viral sequences sampled from each of the other individuals in the cluster are monophyletic, indicating a single origin, with no further transmission to other individuals. Thus, the tree is inconsistent with CC02-CC08 being the original source of infection in this cluster.

About thirteen different species of finches inhabit the Galápagos Islands today, all descendants of a common ancestor from the South American mainland that arrived a few million years ago. Genetically, there are four distinct lineages, but the thirteen species are currently classified among three genera. The first lineage to diverge from the ancestral lineage was the warbler finch (genus Certhidea). Next to diverge was the vegetarian finch (genus Camarhynchus), followed by five tree finch species (also in genus Camarhynchus) and six ground finch species (genus Geospiza). If the six ground finch species have evolved most recently, then which of these is the most logical prediction?

Their genomes should be more similar to each other than are the genomes of the five tree finch species.

Many songbirds breed in North America in the spring and summer and then migrate to Central and South America in the fall. They spend the winter in these warmer areas, where they feed and prepare for the spring migration north and another breeding season. Two hypothetical species of sparrow, A and B, overwinter together in mixed flocks in Costa Rica. In spring, species A goes to the east coast of North America, and species B goes to the west coast. What can you say about the isolating mechanisms of these two species?

Their winter habitat has no bearing on their degree of reproductive isolation.

Mammals have a double circulation. What is meant by this phrase?

There are two circuits; one going to and from the lungs and another going to and from the tissues of the body

If the bacterium Staphylococcus aureus experiences a cost for maintaining one or more antibiotic-resistance genes, what would happen in environments that lack antibiotics?

These bacteria would be outcompeted and replaced by bacteria that have lost these genes.

Which of the following is NOT considered a function of antibodies

They can secrete toxins that are directly antimicrobial

Why should deepwater shrimp on different sides of the isthmus have diverged from each other earlier than shallow-water shrimp?

They have been geographically isolated from each other for a longer time.

In eusocial insects, like ants or bees, how related are the worker ants?

They share 75% DNA

You are studying a group of related fossils, and you notice that a particular trait is present in older fossils, but disappears in more recent species. What does this mean

This means that in more recent species, individuals without the trait had higher fitness

There is an island in the middle of a large river that houses a large population of ants. Damming of the river causes the island to flood and only the highest points of the island are now above water. The ants cannot swim, so are now in multiple isolated populations. Which of the following best describes this event?

This situation represents isolation by vicariance.

Why did the investigators keep the identities of each virus generation a secret from the other researchers developing the phylogenetic tree?

To be sure that only the sequence information was used in the construction of the phylogenetic tree

What was the main mission of the HMS Beagle during the five-year voyage?

To survey and map the coast of South America

Applying the principle of parsimony to the trait "ability to fly," which of the following two phylogenetic trees is better?

Tree 1

A farmer uses triazine herbicide to control pigweed in his field. For the first few years, the triazine works well and almost all the pigweed dies; but after several years, the farmer sees more and more pigweed. Which of these explanations best explains what happened?

Triazine-resistant weeds were more likely to survive and reproduce.

Which two traits evolved along the same branch of your reconstructed phylogeny?

True roots and vascular cells.

Which of the following is a fitness trade-off (compromise)?

Turtle shells provide protection but are heavy and burdensome when moving.

Which of the following is a fitness trade-off (compromise)? A) In some hornbill species, the male helps seal the female in a tree with her nest until the young are ready to fledge. B) Hummingbirds are the best pollinators of certain flowers, but bees are the best pollinators for orchids. C) The strong, thick beak of a woodpecker helps it find insects in trees. D) Turtle shells provide protection but are heavy and burdensome when moving.

Turtle shells provide protection but are heavy and burdensome when moving.

Which of the following is an example of a postzygotic reproductive barrier?

Two fruit flies of different species produce viable, yet sterile offspring

sympatric isolation

Two plant species in a field can often hybridize. The hybrid progeny may become self-fertile through polyploidy, giving rise to a distinct new species.

How is an allopolyploid plant formed?

Two plants of different species interbreed to form a plant of a new species

Temporal Isolation

Two species of orchids bloom at different times of the day preventing them from cross-pollinating.

Over long periods of time, many cave-dwelling organisms have lost their eyes. Tapeworms have lost their digestive systems. Whales have lost their hind limbs. How can natural selection account for these losses?

Under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits

Under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits.

With what other idea of his time was Cuvier's theory of catastrophism most in conflict?

Uniformitarianism

Which of the following statements about transmission across a typical chemical synapse is false?

Vesicles containing neurotransmitters diffuse to the receiving cell's plasma membrane

Why did Darwin document and describe vestigial traits?

Vestigial traits indicate that species c\Change over time. This is an important pattern component of the theory of evolution and is inconsistent with the theory of special creation.

Which of the individuals labeled in the tree is consistent with being the source of this infection cluster? Why?

Viruses from CC01 are found across the tree, which is consistent with CC01 transmitting viruses over time to the other individuals.

Which of the following scientists argued that variation among individuals allows evolution to occur?

Wallace

Which two of these taxa are most closely related?

There is a population of beetles that typically have black wings. A scientist studying these beetles knows that their eggs hatch in early spring, the young insects grow through the late spring and summer, they lay eggs in the early fall, and they die in the early winter. Recently some beetles have been born with white wings. Early in life, the black- and white-winged beetles seem to be very similar in number of mating events, eggs laid, and survival rates, but shortly after laying their eggs, the white beetles die and there are only black-winged beetles during the late fall. Which of the following is a TRUE statement about the beetles?

White- and black-winged beetles have equal fitness.

Many phylogenetic trees are based on DNA sequence similarities. What is the practical result of this similarity? a) Species with very similar DNA will have similar structures, enzymes, and appearance. b) Closely related species will not look similar to each other. c) Artificial selection can bring closely related species even closer to each other. d) Mitochondrial DNA might be different from nuclear DNA.

The same basic internal organs (kidneys, stomach, heart, lungs) are found in frogs, birds, snakes. and rodents. This is primarily an example of a) structural homology. b) genetic correlation. c) inheritance of acquired characteristics. d) developmental homology.

Three populations of crickets look very similar, but the males have courtship songs that sound different. What function would this difference in song likely serve if the populations came in contact?

a behavioral reproductive isolating mechanism

The killing of a virus-infected cell by cytotoxic T cell is an example of

a cell-mediated immune response

What is polyploidy?

a condition in which an organism has more than two complete sets of chromosomes

Prior to the work of Lyell and Darwin, the prevailing belief was that Earth is _____.

a few thousand years old, and populations are unchanging

Refer to the paragraph on dark-eyed junco birds. The UCSD campus male junco population tails were, on average, 36% white, whereas the tails of males from nearby mountain populations averaged 40-45% white. If this observed trait difference were due to a difference in the original colonizing population, it would most likely be due to _____. A) mutations in the UCSD population B) gene flow between populations C) a genetic bottleneck D) a founder effect

a founder effect

An earthquake decimates a ground-squirrel population, killing 98 percent of the squirrels. The surviving population happens to have broader stripes, on average, than the initial population. If broadness of stripes is genetically determined, what effect has the ground-squirrel population experienced during the earthquake?

a genetic bottleneck

Many crustaceans (for example, lobsters, shrimp, and crayfish) use their tails to swim, but crabs have reduced tails that curl under their shells and are not used in swimming. This is an example of _____.

a vestigial trait

Darwin and Wallace were the first to propose _____.

a) natural selection as the mechanism of evolution

What do organisms in domain Bacteria have in common with organisms in domain Archaea but not with organisms in domian Eukarya?

absence of nucleus

In those parts of equatorial Africa where the malaria parasite is most common, the sickle-cell allele constitutes 20 percent of the β hemoglobin alleles in the human gene pool. The sickle-cell allele is pleiotropic (that is, it affects more than one phenotypic trait). Specifically, this allele affects oxygen delivery to tissues and affects one's susceptibility to malaria. Heterozygous individuals who have one normal and one sickle-cell allele have a phenotype that has both costs and benefits. The cost: Under conditions of low atmospheric oxygen availability, individuals heterozygous for this allele can experience life-threatening sickle-cell "crises." The benefit: Such individuals are less susceptible to malaria. Thus, pleiotropic genes/alleles reveal that ________.

adaptations are often compromises

Biologists have found more than 100 species of Amastra on the various Hawaiian Islands, all apparently descended form a common ancestor. This example illustrates

adaptive radiation

The medical condition known as stomach ulcers would most likely be treated using which of the following techniques?

administration of an oral antibiotic

A population of organisms will not evolve if _____.

all individual variation is due only to environmental factors

"Common ancestry" is supported by data from _______.

all of these support the idea of common ancestry

House finches were found only in western North America until 1939, when a few individuals were released in New York City. These individuals established a breeding population and gradually expanded their range. The western population also expanded its range somewhat eastward, and the two populations have recently come in contact. If the two forms were unable to interbreed when their expanding ranges met, it would be an example of ________.

allopatric speciation

Darwin's finches on the Galápagos Islands have diverged primarily via _______ speciation, and exhibit diverse morphologies owing to differences in ________.

allopatric; their diets

How are two different species most likely to evolve from one ancestral species?

allopatrically, after the ancestral species has split into two populations

This type of organism requires considerable parental care

altricial

Which of the following choices lists the correct path of carbon dioxide moving out from the interior of the body?

alveoli--bronchioles--bronchi--trachea--larynx--pharynx

A hybrid zone is properly defined as ________.

an area where mating occurs between members of two closely related species, producing viable offspring

The biological species concept (BSC) is NOT useful for organisms only known from fossils because_________.

an area where mating occurs between members of two closely related species, producing viable offspring

The phenomenon of fusion is likely to occur when, after a period of geographic isolation, two populations meet again and ________.

an increasing number of viable, fertile hybrids is produced over the course of the next 100 generations

Given what we know about evolutionary biology, we expect to find the largest number of endemic species in which of the following geological features, which have existed for at least a few million years?

an isolated ocean island in the tropics

Some beetles and flies have antler-like structures on their heads, much like male deer do. The existence of antlers in beetle, fly, and deer species with strong male-male competition is an example of _____.

analogy

Which of the following is FALSE?

animals that extract food particles suspended in the surrounding water are called fluid feeders

The body's nonspecific lines of defense includes all of the following EXCEPT

antibodies

Methanogens, extreme halophiles and extreme thermophiles are examples of

archaea

Subpopulations often vary genetically because they

are subject to different selective pressures from the larger population.

Scientific theories _____.

are supported by, and make sense of, many observations

Why might some genetically similar species pairs exhibit high levels of reproductive isolation?

ask the teacher

You sequence the genes that code for an important glycolytic enzyme in a moth, a mushroom, a worm, and an alga, and find a high degree of sequence similarity among these distantly related species. This is an example of a) structural homology. b) genetic homology. c) developmental homology. d) analogy/convergent evolution.

Males of different species of the fruit fly Drosophila that live in the same parts of the Hawaiian Islands have different elaborate courtship rituals. These rituals involve fighting other males and making stylized movements that attract females. What type of reproductive isolation does this represent?

behavioral isolation

Which of the types of reproductive barriers listed below corresponds to the following situation: two species of meadowlarks with different mating songs.

behavioral isolation

Which type of reproductive isolation operates to keep the mosquitofish isolated, even when fish from different ponds are reunited in the same body of water?

behavioral isolation

Dogs and gray wolves can interbreed to produce viable, fertile offspring. These species shared a common ancestor recently and have a high degree of genetic similarity, although their anatomies vary widely. Judging from this evidence, which two species concepts are most likely to place dogs and wolves together into a single species?

biological and phylogenetic

Alcanivorax borkumensis is a Gram-negative, marine bacterium. This organsim was found in abundant numbers only after the Gulf Oil Spill in 2010. Interestingly, this organism has the ability to ingest and then degrade hydrocarbon compounds. Scientists are currently looking for ways to utilize this organism in cleaning up oil spills. Such use of this organism would be considered

bioremediation

Crocodiles are more closely related to

birds

Production and disposal of urine occurs in four processes. In the process of filtration, what is being filtered?

blood

Of the following anatomical structures, which is homologous to the bones in the wing of a bird?

bones in the flipper of a whale

New alleles can originate in a population due to mutation. However, most of the genetic variation observed within a population of sexually reproducing organisms is due to

both random fertilization and crossing-over during prophase I of meiosis

The common ancestor between mammals and crocodiles likely had

both tetrapod limbs and an amnion

Oxygen is mostly transported though the body

bound to hemoglobin

Gill pouches in chick, human, and house-cat embryos are an example of a) the inheritance of acquired characters. b) structural homology. c) developmental homology. d) genetic homology.

Which of the following is the best modern definition of evolution? a) inheritance of acquired characters b) survival of the fittest c) change in allele frequencies in a population over time d) descent without modification

Why did Darwin argue that evidence of extinction supports the theory of evolution? a) It shows that lower organisms have died to make way for humans. b) It shows that reproduction is more important than survival of the fittest. c) It shows that the number and types of species have changed over time. d) It shows that nothing lasts forever.

In the figure to the right, the structure labeled "D"

carries CO2 rich blood to the lungs

The role that humans play in artificial selection is to _____.

choose which organisms reproduce

Carnivory in plants has evolved at least 5 times independently, yet there is a great deal of morphological similarity among these groups. This independent evolution of similar traits is called__________.

convergent evolution

On the tree of life, the branch leading to animals is closer to fungi than it is to the branch leading to land plants. Which of the following statements is correct? a)Fungi and animals do not have a common ancestor. b) Animals and plants do not have a common ancestor. c) Animals and land plants are more closely related to each other than either is to fungi. d) Animals and fungi are more closely related to each other than animals are to land plants.

Currently the only predators of Galapagos marine iguanas are Galapagos hawks. Iguana body size is not correlated with risk of hawk predation, although small iguanas can sprint faster than large iguanas. If predators that preferably catch and eat slower iguanas are introduced to the island, iguana body size is likely to ____ in the absence of other factors; the iguanas would then be under ___ selction

decrease....directional

Currently, the only predators of Galápagos marine iguanas are Galápagos hawks. Iguana body size is not correlated with risk of hawk predation, although small iguanas can sprint faster than large iguanas. If predators (for example, cats) that preferentially catch and eat slower iguanas are introduced to the island, iguana body size is likely to ________ in the absence of other factors; the iguanas would then be under ________ selection.

decrease; directional selection

In the figure to the right the region labeled "B" is the

dermis

On the volcanic, equatorial West African island of Sao Tomé, two species of fruit fly exist. Drosophila yakuba inhabits the island's lowlands, and is also found on the African mainland, located about 200 miles away. The very closely related species Drosophila santomea is found at higher elevations and only on Sao Tomé. The two species can hybridize, though male hybrids are sterile. A hybrid zone exists at middle elevations, where hybrids are greatly outnumbered by D. santomea. Studies of the two species' nuclear genomes reveal that D. yakuba on the island is more closely related to mainland D. yakuba than to D. santomea (2n = 4 in both species). Sao Tomé rose from the Atlantic Ocean about 14 million years ago.

descended from an original colony of D. yakuba, of which there are no surviving members; the current island D. yakuba represent a second colonization event from elsewhere

1) Which of the following is the best modern definition of evolution? A) descent with modification B) change in the number of genes in a population over time C) survival of the fittest D) inheritance of acquired characters

descent with modification

Cotton-topped tamarins are small primates with tufts of long white hair on their heads. While studying these creatures, you notice that males with longer hair get more opportunities to mate and father more offspring. To test the hypothesis that having longer hair is adaptive in these males, you should _____.

determine if hair length is heritable

A researcher wants to know if gene flow is contributing to evolution of drought tolerance of pitcher plants in a specific bog. As a control, she should

determine if the population is in Hardy—Weinberg equilibrium.

Similar gill pouches in embryos of a chick, human, and cat are an example of ________.

developmental homology

If there is no gene flow, the curve shifts to the left or to the right, and the population size consequently increases over successive generations, which of the following is most likely occurring? A) immigration or emigration B) directional selection C) disruptive selection D) genetic drift

directional selection

In seedcracker finches from Cameroon, small- and large-billed birds specialize in cracking soft and hard seeds, respectively. If long-term climatic change resulted in all seeds becoming hard, what type of selection would then operate on the finch population?

directional selection

Darwin and Wallace's theory of evolution by natural selection was revolutionary because it _____ A. proved that individuals acclimated to their environment over time B. was the first time a biologist had proposed that species changed through time C. was the first theory to refute the ideas of special creation D. dismissed the idea that species are constant and emphasized the importance of variation and change in populations

dismissed the idea that species are constant and emphasized the importance of variation and change in populations

Darwin and Wallace's theory of evolution by natural selection was revolutionary because it _____.

dismissed the idea that species are constant and emphasized the importance of variation and change in populations

Which of the following is most likely to produce an African butterfly species in the wild whose populations show two strikingly different color patterns?

disruptive selection

A researcher notices that in a certain moth species, some females prefer to feed and lay eggs on domesticated solanaceous plants like potatoes and tomatoes. Other females prefer to feed and lay eggs on wild solanaceous plants like Datura. Both male and female moths primarily use scent to find these plants from afar. Females tend to mate where they feed, and the researcher finds a genetic basis for scent preference in these moths. Based on the above information, what might be occurring in this moth species?

divergence in sympatry

Which of the following, if discovered, could refute our current understanding of the pattern of evolution?

diverse fossils of mammals in Precambrian rock

Pyrenestes sanguineusis, is a specieas of ground finches found in Africa. Within this species there is selective pressure for largebills, so that the birds can crack open large seeds or for small-bills so that birds can reach into leaves to harvest soft, small seeds. The intermediate sized bills are too large to harvest small seeds and too small to crack open the large seeds. Birds in this intermediate bill-size are often malnourished. This is an example of

diversifying selection

Ernst Mayr's biological species concept

does not apply to organisms that reproduce asexually.

Evolutionary theory predicts that species are related, not independent. Four of the following examples provide support for this prediction, but one is irrelevant. Which one of these examples does not support the claim that species are related? a) The endostyle of lancelets (invertebrate chordates) and the thyroid gland of vertebrates develop similarly, and both produce iodinated proteins. b) Ground squirrel species found on the north and south sides of the Grand Canyon are very similar to each other. c) All prokaryotes and eukaryotes use DNA to carry their genetic information. d) Before synthetic insulin was available, diabetics used injections of purified pig insulin to manage their disease. e) Many dinosaurs and other organisms went extinct following a huge asteroid impact at the end of the Cretaceous.

Researchers have found fossils of Eocene horse species in Colorado. Deeper deposits contain smaller species, and more recent deposits contain larger species. How does this observation support the theory of evolution? a) It suggests that species are unchanging and of recent origin. b) It does not support the theory of evolution. c) It shows that all species are related to each other. d) It proves that environments have changed over time. e) It provides evidence that species change over time.

Dobzhansky-Muller Model

emphasizes gene interaction.

Humans are considered to be both an ____ and an ___

endotherm....osmoregulator

Lipopolysaccharide (LPS) is a component of the outer membrane in some bacterial species. LPS can elicit a strong response form animal immune cells that often results in exacerbating the infection due to the fact the LPS can destroy immune cells. LPS is considered a(n)

endotoxin

After the drought of 1977, researchers on the island of Daphne Major hypothesized that medium ground finches that had large, deep beaks survived better than those with smaller beaks because they could more easily crack and eat the tough Tribulus cistoides fruits. If this hypothesis is correct, what would you expect to observe if a population of these medium ground finches colonizes a nearby island where T. cistoides is the most abundant food for the next 1000 years? Assume that (1) even the survivors of the 1977 drought sometimes had difficulty cracking the tough T. cistoides fruits and would eat other seeds when offered a choice; and (2) food availability is the primary limit on finch fitness on this new island.

evolution of yet larger, deeper beaks over time

If limited resources are concentrated males will compete for mating opportunities by.....

fighting for and defending territory

Select the correct order for the events listed.

first boney fish, first land plants, first reptiles, first flowering plants, first mammals

Soon after the island of Hawaii rose above the sea surface (somewhat less than 1 million years ago) and organisms colonized the island, the evolution of life on this new island should have been most strongly influenced by ________.

founder effects

Which of the following is NOT associated with the process of inflammation?

gain of function

Rocky Mountain juniper (Juniperus scopulorum) and one-seeded juniper (J. monosperma) have overlapping ranges. Pollen grains (which contain sperm nuclei) from one species are unable to germinate and make pollen tubes to bring the sperm nuclei to the female ovules (which contain egg cells) of the other species. These two juniper species are kept separate by ________.

gametic isolation

What does the biological species concept use as the primary criterion for determining species boundaries?

gene flow

Which of thefollowing does not tend to promote speciation?

gene flow

In hybrid zones where reinforcement is occurring, you should see a decline in ________.

gene flow between distinct gene pools

The separation of H. erectus and H. floresiensis and subsequent evolution of H. floresiensis illustrates

genetic drift

Which of the following must exist in a population before natural selection can act upon that population?

genetic variation among individuals

One defining characteristic of allopatric speciation is____________.

geographic isolation

Which of the following lists structures in the order in which fluid flows through them?

glmerulus--Bowman's capsule--proximal tubule--loop of Henle--distal tubule

Dog breeders maintain the purity of breeds by keeping dogs of different breeds apart when they are fertile. This kind of isolation is most similar to which of the following reproductive isolating mechanisms?

habitat isolation

Two populations of birds with somewhat different coloration live on opposite sides of a peninsula. The habitat between the populations is not suitable for these birds. When birds from the two populations are brought together, they produce young whose appearance is intermediate between the two parents. These offspring will breed with each other or with birds from either parent population, and all offspring of these pairings appear intermediate to various degrees. What keeps the two populations separate?

habitat isolation

Which of the types of reproductive barriers listed below corresponds to the following situation: two species of moose, one living in Russia and the other living in Canada

habitat isolation

If H. floresiensis were reunited with H. erectus at a much later date, but the two populations could no longer interbreed, it would be correct to conclude that H. floresiensis

had evolved reproductive barriers

If you say that a ground squirrel has greater evolutionary fitness than another ground squirrel in the same population, you mean that the animal

has more offspring that survive and reproduce themselves.

In the formula for determining a population's genotype frequencies, the "2" in the term 2pq is necessary because _____. A) the population is diploid B) heterozygotes can come about in two ways C) the population is doubling in number D) heterozygotes have two alleles

heterozygotes can come about in two ways

Which of the following reduces gene flow between the gene pools of the two species on Sao Tomé, despite the existence of hybrids?

hybrid sterility

Reinforcement is most likely to occur when ________.

hybrids have lower fitness than either parent population

Some human infants, especially those born prematurely, suffer serious repiratory failure. This most probably relates to which of the following?

inadequate production of surfactant

Diuretic are a class of drugs that make the epithelium of the collecting duct less permeable to water. How would this affect kidney function?

increase the concentration of water in urine

To increase the effectiveness of exchange surfaces in the lungs and in the intestins, evolutionary pressures have

increased the surface area available for exchange

After the drought of 1977, researchers hypothesized that on the Galápagos island Daphne Major, medium ground finches with large, deep beaks survived better than those with smaller beaks because they could more easily crack and eat the tough Tribulus cistoides fruits. A tourist company sets up reliable feeding stations with a variety of bird seeds (different types and sizes) so that tourists can get a better look at the finches. Which of these events is now most likely to occur to finch beaks on this island?

increased variation in beak size and shape over time

tourist company sets up reliable feeding stations with a variety of bird seeds (different types and sizes) so that tourists can get a better look at the finches. Which of these events is now most likely to occur to finch beaks on this island?

increased variation in beak size and shape over time

Natural selection is based on all of the following statements EXCEPT

individuals adapt to their environments and thereby evolve

Disruptive selection favors________.

individuals at both extremes of the range of phenotypes

Directional selection favors________.

individuals at only one extreme of the range of phenotypes

Stabilizing selection favors______________.

individuals with intermediate phenotypes

Which of the following processes is NOT involved in heat exchange between an animal and its environment?

induction

Which of the following chemical signals is released from a virally infected cell in an attempt to prepare neighboring cells for a possible viral infection?

interferon (IFN)

What fills the spaces between cells in your tissues?

interstitial fluid

It has been observed that organisms on islands are different from, but closely related to, similar forms found on the nearest continent. This is taken as evidence that ____.

island forms are descended from mainland forms

The greatest number of endemic species is expected in environments that are _____.

isolated and show little ecological diversity

Which of the following statements describes pepsin?

it begins the hydrolysis of proteins in the stomach

Blood is best classified as connective tissue because

its cells can be separated form each other by an extracellular matrix

Which of the following is NOT a function of the excretory system?

maintenance of salt balance

Fossils of Thrinaxodon, a species that lived during the Triassic period, have been found in both South Africa and Antarctica. Thrinaxodon had a reptile-like skeleton and laid eggs, but small depressions on the front of its skull suggest it had whiskers and, therefore, fur. Thrinaxodon may have been warm-blooded. The fossils of Thrinaxodon are consistent with the hypothesis that ________.

mammals evolved from a reptilian ancestor

All cellular movement is based on contractile system involving

microtubules and microfilaments

Why would you expect selection on human birth weight to be stabilizing rather than directional?

mortality increases with both smaller and larger birth weight compared to the optimal birth weight of about 7.5 pounds. Significantly smaller babies are more likely to be premature or undernourished, and thus less likely to survive. Significantly larger babies may cause difficulties in delivery, putting both the baby and mother at greater risk and stress during childbirth. Thus, babies close to the modal birth weight are most likely to survive and grow into adults, thereby increasing the relative frequency of alleles for intermediate birth size in the population.

In the figure to the right, letter "A" represents which type of neuron?

motor neuron

Genetic variation ________.

must be present in a population before natural selection can act upon the population

natural selection is generally limited to modifying structures that were present in previous generations and/or in previous species

In complex animals, which of the following organ systems would you NOT expect to hae a large epithelial surface area?

nervous system

Which of the following examples in an INCORRECT association?

nervous tissue--contractile unit in the body

15) For a biologist studying a small fish population in the lab, which Hardy-Weinberg condition is easiest to meet? A) no selection B) no genetic drift C) no gene flow D) no mutation

no gene flow

For a biologist studying a small fish population in the lab, which Hardy—Weinberg condition is easiest to meet?

no gene flow

DDT was once considered a "silver bullet" that would permanently eradicate insect pests. instead, DDT is largely useless against many insects. which would have prevented this evolution of DDT resistance in insect pests?

none of the insect pests would have genetic variations that resulted in DDT resistance

Pseudogenes are _____.

nonfunctional vestigial genes

When Cuvier considered the fossils found in the vicinity of Paris, he concluded that the extinction of species _____.

occurs, but that there is no evolution

An adaptation that confers a selective advantage to a species is:

often constrained by some cost to the species.

a farmer uses triazine herbicide to control pigweed in his field. For the first few years, the triazine works well an almost all the pigweed dies; but after several years, the farmer sees more and more pigweed. Which of these explanations best describes this observation?

only triazine-resistant weeds survived and reproduced, so each year more pigweed was triazine-resistant

Which of the following correctly lists the order of organs in the human digestive system?

oral cavity--pharynx--esophagus--stomach--small intestine--large intestine

Oxygen moves form blood into the interstitial fluid and then to the body cells because

oxygen diffuses from a region of higher partial pressure to a region of lower partial pressure

In 1890, antibody therapy was used to treat tetanus, when serum from immunized horses was injected into patients with severe tetanus in an attempt to neutralize the tetanus toxin, and prevent the dissemination of the diease. This is an example of ____ immunity

passive

You are examining an unknown life form extracted from a sample taken in the deep sea. Which of the following clues would convince you that the life form is bacterial?

peptidoglycan in their cell wall material

Microbiologiests use the Gram stain to aid in the identification of bacteria. What is the major difference between Gram positive and Gram negative bacteria?

persence or absence of an outer plasma membrane

If you lay your forearm along the table, you can rotate it so that your hand changes from a palm-down to palm-up position. This is possible because your radius and ulna join at a

pivot joint

Following maturation and activation, B cells proliferate and differentiate into _______ a cell type responsible for secreting large amounts of antibody

plasma cells

Which of the following breeding systems typically leads to sexual dimorphism, where the males are larger and/or more ornate than females?

polygyny

A biological species is defined as a

population of group of populations whose membranes have the potential to interbreed and produce fertile offspring

On the volcanic, equatorial West African island of Sao Tomé, two species of fruit fly exist. Drosophila yakuba inhabits the island's lowlands, and is also found on the African mainland, located about 200 miles away. At higher elevations, and only on Sao Tomé, is found the very closely related Drosophila santomea. The two species can hybridize, though male hybrids are sterile. A hybrid zone exists at middle elevations, but hybrids there are greatly outnumbered by D. santomea. Studies of the two species' nuclear genomes reveal that D. yakuba on the island is more closely related to mainland D. yakuba than to D. santomea (2n = 4 in both species). Sao Tomé rose from the Atlantic Ocean about 14 million years ago. If the low number of hybrid flies in the hybrid zone, relative to the number of D. santomea flies there, is due to the fact that hybrids are poorly adapted to conditions in the hybrid zone, and if fewer hybrid flies are produced with the passage of time, these conditions will most likely lead to ________.

reinforcement

When nonrandom mating occurs in a population so that individuals prefer to mate with similar individuals, allele frequencies should

remain the same, but homozygotes will be overrepresented in the population.

Functions of the lymphatic system include

return of fluid to the circulatory system

Which of the following correctly demonstrates the flow of blood through the mammalian heart?

right atrium--right ventricle--pulmonary artery--left atrium--left ventricle--aorta

When you hold your breath, which of the following blood-gas changes leads initially to the urge to breathe again?

rising carbon dioxide concentration

The figure to the right is a cartoon of the cells that make up a tubule within the kidney

simple cuboidal epithelium

Food moves along the majority of the digestive tract as the result of contractions by

smooth muscles

Which division of the human nervous system carries signals to skeletal muscles?

somatic nervous system

Antigens are

specific molecules, or parts of molecules that the body recognizes as foreign

based on the information in the figure, human birth illustrates

stabilizing natural selection

Most Swiss starlings produce four to five eggs in each clutch. Starlings producing fewer or more than this have reduced fitness. Which of the following terms best describes this situation?

stabilizing selection

A physician orders a culture form a skin infection. Microscopic examination of the culture reveals spherical-shaped bacteria arranged in clusters. This arrangement is correctly referred to as

staphylococci

Which of Darwin's ideas had the strongest connection to his reading of Malthus's essay on human population growth?

struggle for existence

Suppose you are about to give a speech in one of your classes. You begin to feel nervous, your mouth gets dry and your heart rate increases. This is most likely due to stimulation by the

sympathetic division of the autonomic nervous system

In a hypothetical situation, a certain species of flea feeds only on pronghorn antelopes. In the western United States, pronghorns and cattle often associate with one another in the same open rangeland. Some of these fleas develop a strong preference for cattle blood and mate only with other fleas that prefer cattle blood. The host mammal can be considered as the fleas' habitat. If this situation persists, and new species evolve, this would be an example of ________.

sympatric speciation and habitat isolation

Beetle pollinators of a particular plant are attracted to its flowers' bright orange color. The beetles not only pollinate the flowers but mate while inside of the flowers. A mutant version of the plant with red flowers becomes more common with the passage of time. A particular variant of the beetle prefers the red flowers to the orange flowers. Over time, these two beetle variants diverge from each other to such an extent that interbreeding is no longer possible. What kind of speciation has occurred in this example, and what has driven it?

sympatric speciation; habitat isolation

Describe the ways that these populations of A. carolinensis deviate from assumptions of Hardy-Weinberg equilibrium (the conditions that would be necessary for the populations to not evolve).

t the evolutionary change would occur in the opposite direction; the average toepads would become smaller on the invaded islands compared to un-invaded islands. Selection for larger toepads appears to be occurring. Mutation is certainly occurring in the populations (as it does in all species), although it likely has a very small effect at this time scale. The populations on each island are likely to be fairly small, so drift is occurring. Gene flow among populations is unknown, but it is likely to be low, since new invasions of islands appear to be rare. Nonrandom mating among the lizards may be occurring, although there is no evidence of this process described in the experiment.

A small number of birds arrive on an island from a neighboring larger island. This small population begins to adapt to the new food plants available on the island as selection favors those birds with larger beaks. About twice a year, one or two more birds from the neighboring island arrive. These new arrivals ________.

tend to retard adaptation to the new food plants

A tornado passes over a lake with a large and diverse population of frogs. The tornado sucks up some of the water along with a male and female frog. The two frogs are dropped in a large lake 20 miles away that has no frogs living in it. These two frogs mate and populate the lake, which results in a population that is very different from the source lake. This story, in addition to having a happy ending, is an example of ______________.

the Founder Effect

Biological fitness is best defined as

the ability of an individual to produce offspring that survive and reproduce, relative to other individuals in the population.

Whenever diploid populations are in Hardy-Weinberg equilibrium at a particular locus, _____. A) the allele's frequency should not change from one generation to the next B) natural selection, gene flow, and genetic drift are acting equally to change an allele's frequency C) two alleles are present in equal proportions D) individuals within the population are evolving

the allele's frequency should not change from one generation to the next

Veins are distinguished from arteries based on all of the following EXCEPT

the amount of oxygen present in the blood

Of the following anatomical structures, which is homologous to the bones in the wing of a bat?

the bones in the flipper of a whale

Catastrophism was Cuvier's attempt to explain the existence of _____.

the fossil record

The Afrikaner population of Dutch settlers in South Africa is descended mainly form a few colonists. Today, the Afrikaner populaiton has an unusually high frequency of the gene that causes Huntington's disease, because those original Dutch colonists just happened to carry that gene with unusually high frequency. This scenario illustrates

the founder effect

The emergence of a new insect species over a period of time with many transitional forms identified in the fossil record would support which of the following theories?

the gradualism model

The distinction between prezygotic and postzygotic isolation is whether

the isolation occurs before or after fertilization.

An example of a properly functioning homeostatic control system is seen when

the kidneys exrete salt into the urine when dietary salt levels rise

In Darwin's thinking, the more closely related two organisms are__________.

the more recently they shared a common ancestor

How does artificial selection differ from natural selection?

the only real difference is that humans, and not the environment is doing the selecting

Using the figure to the right, the structure labeled "E" is responsible for

the production of bicarbonate to neutralize chyme

Air rushes into the lungs of humans during inhalation because

the rib muscles and diapharagm contract, increasing the lung volume

If modern day organisms are DISTANTLY related in an evolutionary sense, then one should predict that __________.

they would share fewer DNA sequence similarities than two more closely related organisms

Which of the following is NOT a function of skeletons?

to add weight

which of the following statements regarding sexual selection is FALSE

traditional gender roles established by sexual selection are fixed

Which of the following describes intrasexual competition?

two male pheasants fighting for territory

The data collected by the researchers indicate that ________.

two-way migration of squirrels occurred across the bridge but without hybridization

This kidney is responsible for producing which of the following fluids?

urine

Which of the following evidence most strongly supports the common origin of all life on Earth? All organisms _____.

use essentially the same genetic code

HIV's genome of RNA includes the code for reverse transcriptase (RT), an enzyme that acts early in infection to synthesize a DNA genome off of an RNA template. The HIV genome also codes for protease (PR), an enzyme that acts later in infection by cutting long viral polyproteins into smaller, functional proteins. Both RT and PR represent potential targets for antiretroviral drugs. Drugs called nucleoside analogs (NA) act against RT, whereas drugs called protease inhibitors (PI) act against PR. 7) Which of the following represents the treatment option most likely to avoid the evolution of drug-resistant HIV (assuming no drug interactions or side effects)? A) using a series of NAs, one at a time, and changed about once a week B) using a single PI, but slowly increasing the dosage over the course of a week C) using high doses of NA and a PI at the same time for a period not to exceed one day D) using moderate doses of NA and two different PIs at the same time for several months

using moderate doses of NA and two different PIs at the same time for several months

Analysis of sediments shows that Death Valley, California, was once a large, continuous complex of lakes and marshes. Today it is a desert with tiny, isolated springs. Each spring has its own species of desert pupfish. This is an example of which concept? vicariance dispersal biological species concept morphological species concept

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